Carbonio Storage#

Introduction#

Each Carbonio installation consists of one primary volume and a variable number of secondary volumes. The purpose of the Carbonio Storage module is to manage the secondary volumes and to move items between them.

Items can be moved according using the Hierarchical Storage Management (Hierarchical Storage Management), a policy-based technique: One of the most useful is for example to reserve the most performing storage for intensive I/O operation and for data with frequent access, while the less performing will manage older data.

The remainder of this section describes volumes and their management, policies, HSM, and various advanced techniques.

The Basics: Types of Stores and Their Uses#

Carbonio allows for two different types of stores:

Index Store

A store that contains information about your data that is used by Apache Lucene to provide indexing and search functions.

Data Store

A store that contains all your Carbonio data organized in a MySql database.

You can have multiple stores of each type, but only one Index Store, one Primary Data Store and one Secondary Data Store can be set as Current (meaning that is currently used by Carbonio).

Primary and Secondary Data Stores#

A data store in Carbonio can be either a Primary Data Store or a Secondary Data Store.

Data is moved between the current Primary Data Store and the current Secondary Data Store according to a defined policy.

Volumes#

Three types of volumes are defined by Carbonio:

Primary Current

A volume where data are written upon arrival.

Secondary Current

A volume where data are written following the application of a HSM policy.

Not Current

Volumes not set as Current and on which data is written only by specific manual operations.

By default, items are placed in the Primary Current volume of the destination server.

Centralized Storage#

The Centralized Storage feature allows to use an S3 bucket to host data coming from multiple servers at the same time sharing the same directory structure, as opposed to “independent” volumes which are self-contained and whose directory structure is strictly related to the server and volume itself.

This allows for better data management in large multistore environments and greatly improves mailbox move speed.

Two important aspects of centralized storage that should be taken into account before deloying are the following

  1. Item deduplication is lost

  2. Only S3 buckets can be used for centralized storage

Setting up Centralized Storage#

In order to set up a bucket for centralized storage, a few steps are necessary. The procedure is described below and guides you from the creation of the bucket up to the association of the new Storage to multiple Mailstore & Provisioning Roles.

The procedure is the same for all types of supported buckets, although depending on the type of the bucket, either the syntax, or some of the parameter may slightly change. For example, the URL parameter represents the API endpoint of the Object Storage and needs to be written in a format understandable by the Object Storage itself.

In our example, we use an S3 Bucket; to set up a different type of bucket simply use the appropriate command for it.

  1. Create an S3 bucket using the command doCreateBucket

    zextras$ carbonio core doCreateBucket S3 MyBucketName \
    MyBucketUser MyBucketPassword ALabelForMyBucket url \
    http://s3nas.example.com:9000
    

    In this example, we use the following values:

    • S3 as the type of bucket

    • BucketName as the name of the bucket, which must coincide with the name on the remote provider, otherwise the command will fail

    • X58Y54E5687R543 as the remote username

    • abCderT577eDfjhf as the remote password

    • My_New_Bucket is a label given to the bucket

    • https://example_bucket_provider.com is the endpoint to which Carbonio Storage connects to the bucket

      Note

      Pay attention to the format of the URL, because some provider might require that also the port be specified as part of the URL or that the IP address be used instead of the URL.

    When successful, the command outputs the bucket UUID, that is, a string the uniquely identifies the bucket, for example 60b8139c-d56f-4012-a928-4b6182756301. Take note of it because it is required in the remainder of the procedure.

  2. Test the connection using the bucket ID received in the previous step (60b8139c-d56f-4012-a928-4b6182756301):

    zextras$ carbonio core testS3Connection 60b8139c-d56f-4012-a928-4b6182756301
    

    If the command is successful you will see the message connection ok.

  3. On the first Mailstore & Provisioning Node, create a volume associated to the bucket:

    zextras$ carbonio powerstore doCreateVolume S3 Store_01 secondary  \
    60b8139c-d56f-4012-a928-4b6182756301 volume_prefix Main_Volume Centralized true
    

    In this example, these values are used:

    • S3: the type of bucket

    • Store_01: the volume name as defined on the server on which the command is executed

    • secondary: the type of the volume

    • 60b8139c-d56f-4012-a928-4b6182756301: the bucket ID as received in step 1

    • volume_prefix Main_Volume: a label assigned to the volume, used for quick searches (e.g., main_vol)

    • centralized true: the volume is centralized and can be used by multiple Mailstore & Provisioning

  4. Set the volume to current, to let it receive data immediately, using command:

    zextras$ carbonio powerstore doUpdateVolume S3 Store_01 secondary current_volume true
    

    In this example, these values are used:

    • S3: the type of bucket

    • Store_01: the volume name as defined on the server on which the command is executed

    • secondary: the type of the volume

  5. Once the Centralized Volume has been created, you need to copy the Centralized Volume’s configuration from the first server to all mailbox servers and add it to the volume list. To do so, on all other Mailstore & Provisioning that run the following commands:

    zextras$ carbonio powerstore doCreateVolume Centralized mailbox_01.example.com Store_01
    

    In this example, these values are used:

    • S3: the type of bucket

    • Store_01: the volume name as defined on the server on which the command is executed

    • mailbox_01.example.com is the _servername_ of the server on which the volume was defined and created.

    The second command that needs to be run is the one reported in the previous step:

    zextras$ carbonio powerstore doUpdateVolume S3 Store_01 secondary current_volume true
    

Centralized Storage Structure#

Storage Structure Data is stored in a Centralized Volume plainly, as the main directory of the volume contains a single empty directory for each server connected to the volume and a directory for each mailbox stored in it at the very same level.

In the following example, servers 3aa2d376-1c59-4b5a-94f6-101602fa69c6 and 595a4409-6aa1-413f-9f45-3ef0f1e560f5 are both connected to the same Centralized Volume, where 3 mailboxes are stored. As you can see, the effective server where the mailboxes are hosted is irrelevant to the storage:

_
|- 3aa2d376-1c59-4b5a-94f6-101602fa69c6/
|- 595a4409-6aa1-413f-9f45-3ef0f1e560f5/
|- ff46e039-28e3-4343-9d66-92adc60e60c9/
\
 |-- 357-104.msg
 |-- 368-115.msg
 |-- 369-116.msg
 |-- 373-120.msg
 |-- 374-121.msg
 |-- 375-122.msg
 |-- 376-123.msg
 |-- 383-130.msg
|- 4c022592-f67d-439c-9ff9-e3d48a8c801b/
\
 |-- 315-63.msg
 |-- 339-87.msg
 |-- 857-607.msg
 |-- 858-608.msg
 |-- 859-609.msg
 |-- 861-611.msg
 |-- 862-612.msg
 |-- 863-613.msg
 |-- 864-614.msg
 |-- 865-615.msg
 |-- 866-616.msg
 |-- 867-617.msg
 |-- 868-618.msg
|- dafd5569-4114-4268-9201-14f4a895a3d5/
\
 |-- 357-104.msg
 |-- 368-115.msg
 |-- 369-116.msg
 |-- 373-120.msg
 |-- 374-121.msg
 |-- 375-122.msg
 |-- 376-123.msg
 |-- 383-130.msg
 |-- 384-131.msg

Volume Management#

Both primary and secondary volumes can be created on either local storage or on supported third-party storage solutions.

Carbonio Volumes#

A volume is a distinct entity (path) on a filesystem with all the associated properties that contain Carbonio Blobs.

Volume Properties#

All Carbonio volumes are defined by the following properties:

  • Name: A unique identifier for the volume

  • Path: The path where the data is going to be saved. The zextras user must have r/w permissions on this path.

  • Compression: Enable or Disable the file compression for the volume

  • Compression Threshold: The minimum file size that will trigger the compression. Files under this size will never be compressed even if the compression is enabled.

  • Current: A Current volume is a volume where data will be written upon arrival (Primary Current) or HSM policy application (Secondary Current).

Local Volumes#

Local Volumes (i.e., FileBlob type) can be hosted on any mountpoint on the system regardless of the mountpoint’s destination and are defined by the following properties:

  • Name: A unique identifier for the volume

  • Path: The path where the data is going to be saved. The zextras user must have r/w permissions on this path

  • Compression: Enable or Disable file compression for the volume

  • Compression Threshold: the minimum file size that will trigger the compression. Files under this size will never be compressed even if compression is enabled.

Current Volumes#

A Current Volume is a volume where data will be written upon arrival (Primary Current) or HSM Policy Application (Secondary Current). Volumes not set as Current won’t be written upon except by specific manual operations such as the Volume-to-Volume move.

Volume Management with Carbonio Storage#

The commands to manage volumes are basically three: carbonio powerstore doCreateVolume [storeType] | zextras$ doUpdateVolume [storeType] | doDeleteVolume [name]

While volume deletion requires only the volume name, the storeType argument in the other two operations is mandatory and it is always on the first position and accepts any one value corresponding to an S3-Compatible Services. The arguments that follow in the command now depend on the selected storeType.

The parameters required by these commands may differ depending on the [type] of volume to be defined, which is one of the following.

  • FileBlob (Local)

  • Alibaba

  • Ceph

  • OpenIO

  • Swift

  • Cloudian (S3 compatible object storage)

  • S3 (Amazon and any S3-compatible solution not explicitly supported)

  • Scality (S3 compatible object storage)

  • EMC (S3 compatible object storage)

  • Custom S3

Hierarchical Storage Management#

Note

The HSM feature requires a separate license, therefore it may not be available on your Carbonio installation.

The Hierarchical Storage Management Technique#

HSM is a data storage technique that moves data between different stores according to a defined policy.

The most common use of the HSM technique is the move of older data from a faster-but-expensive storage device to a slower-but-cheaper one based on the following premises:

  • Fast storage costs more.

  • Slow storage costs less.

  • Old data will be accessed much less frequently than new data.

The advantages of the HSM technique are clear: Lowering the overall storage cost since only a small part of your data needs to be on costly storage, and improving the overall user experience.

Stores, Volumes, and Policies#

Using HSM requires a clear understanding of some related terms:

  • Primary Store: The fast-but-expensive store where all your data is initially placed.

  • Secondary Store: The slow-but-cheap store where older data will be moved to.

Moving Items between Stores#

The main feature of the Carbonio Storage module is the ability to apply defined HSM policies.

The move can be triggered by starting the doMoveBlobs operation through the CLI.

Once the move is started, the following operations are performed:

  • Carbonio Storage scans through the Primary Store to see which items comply with the defined policy.

  • All the Blobs of the items found in the first step are copied to the Secondary Store.

  • The database entries related to the copied items are updated to reflect the move.

  • If the second and the third steps are completed successfully (and only in this case), the old Blobs are deleted from the Primary Store.

The Move operation is stateful - each step is executed only if the previous step has been completed successfully - so the risk of data loss during a Move operation is nonexistent.

doMoveBlobs#

The doMoveBlobs Operation of Carbonio Storage#

The doMoveBlobs is the heart of Carbonio Storage.

It moves items between the Current Primary Store and the Current Secondary Store according to the proper HSM policy.

The move is performed by a transactional algorithm. Should an error occur during one of the steps of the operation, a rollback takes place and no change will be made to the data.

Once Carbonio Storage identifies the items to be moved, the following steps are performed:

  • A copy of the Blob to the Current Secondary Store is created.

  • The Carbonio Database is updated to notify Carbonio of the item’s new position.

  • The original Blob is deleted from the Current Primary Store.

What is Moved?#

Every item that complies with the specified HSM policy is moved.

Example

The following policy:

message,document:before:-20day
message:before:-10day has:attachment

will move all emails and documents older than 20 days along with all emails older than 10 days that contain an attachment.

Warning

By default, results from the Trash folder do not appear in any search–and this includes the HSM Policy. In order to ensure that all items are moved, add “is:anywhere” to your policy.

Policy Order#

All conditions for a policy are executed in the exact order they are specified. Carbonio Storage will loop on all items in the Current Primary Store and apply each separate condition before starting the next one.

This means that the following policies

message,document:before:-20day
message:before:-10day has:attachment
message:before:-10day has:attachment
message,document:before:-20day

applied daily on a sample server that sends/receives a total of 1000 emails per day, 100 of which contain one or more attachments, will have the same final result. However, the execution time of the second policy will probably be slightly higher (or much higher, depending on the number and size of the emails on the server).

This is because in the first policy, the first condition (message,document:before:-20day) will loop on all items and move many of them to the Current Secondary Store, leaving fewer items for the second condition to loop on.

Likewise, having the message:before:-10day has:attachment as the first condition will leave more items for the second condition to loop on.

This is just an example and does not apply to all cases, but gives an idea of the need to carefully plan your HSM policy.

Executing the doMoveBlobs Operation (a.k.a. Applying the HSM Policy)#

Applying a policy means running the doMoveBlobs operation in order to move items between the Primary and Secondary store according to the defined policy.

Carbonio Storage gives you two different options:

  • Via the CLI

  • Through Scheduling

Warning

Items in Trash or dumpster folders are not moved to the secondary store by the HSM module. Currently, there is no option to define a policy for Trash and dumpster.

To apply the HSM Policy via the CLI, run the following command as the zextras user

zextras$ carbonio powerstore doMoveBlobs

Policy Management#

What is a Policy?#

An HSM policy is a set of rules that define what items will be moved from the Primary Store to the Secondary Store when the doMoveBlobs operation of Carbonio Storage is triggered, either manually or by scheduling.

A policy can consist of a single rule that is valid for all item types (Simple policy) or multiple rules valid for one or more item types (Composite policy).

Policy Examples#

Here are some policy examples. To see how to create the policies in the Carbonio Storage module, see below.

  • “Move all items older than 30 days”

  • “Move emails older than 15 days and items of all other kinds older than 30 days”

  • “Move calendar items older than 15 days, Carbonio Files items older than 20 days and all emails in the Archive folder”

Defining a Policy#

Policies can be defined from the CLI using one of the two policy management commands available.

zextras$ carbonio powerstore setHSMPolicy hsm_policy
zextras$ carbonio powerstore +setHsmPolicy hsm_policy

These command share the same syntax; the difference is that setHSMPolicy creates new policies, replacing existing one, while +setHSMPolicy adds policies to existing ones.

Carbonio Storage and S3 buckets#

Primary and Secondary volumes created with Carbonio Storage can be hosted on S3 buckets, effectively moving the largest part of your data to secure and durable cloud storage.

S3-compatible Services#

While any storage service compatible with the Amazon S3 API should work out of the box with Carbonio Storage, listed here are the only officially supported platforms:

  • FileBlob (standard local volume)

  • Amazon S3

  • EMC

  • OpenIO

  • Swift

  • Scality S3

  • Cloudian

  • Custom S3 (any unsupported S3-compliant solution)

Primary Volumes and the “Incoming” Directory#

In order to create a remote Primary Store on a mailbox server a local “Incoming” directory must exist on that server. The default directory is /opt/|carbonio|/incoming; you can check or modify the current value using these commands:

zextras$ carbonio config server get $(zmhostname) attribute incomingPath
zextras$ carbonio config server set $(zmhostname) attribute incomingPath value /path/to/dir

Local Cache#

Storing a volume on third-party remote storage solutions requires a local directory to be used for item caching, which must be readable and writable by the |carbonio| user.

If the Local Cache directory is not set, you won’t be able to create any secondary volume on an S3-compatible device or service.

Warning

Failing to correctly configure the cache directory will cause items to be unretrievable, meaning that users will get a No such BLOB error when trying to access any item stored on an S3 volume.

Bucket Setup#

Carbonio Storage doesn’t need any dedicated setting or configuration on the S3 side, so setting up a bucket for your volumes is easy. Although creating a dedicated user bucket and access policy are not required, they are strongly suggested because they make it much easier to manage.

All you need to start storing your secondary volumes on S3 is:

  • An S3 bucket. You need to know the bucket’s name and region in order to use it.

  • A user’s Access Key and Secret.

  • A policy that grants the user full rights on your bucket.

Bucket Management#

A centralized Bucket Management UI is available in the Carbonio Carbonio Admin Panel. This facilitates saving bucket information to be reused when creating a new volume on an S3-compatible storage instead of entering the information each time.

To access the Bucket Management UI, access Carbonio's Carbonio Admin Panel, then go to Mailstore ‣ Global Servers ‣ Bucket List.

Any bucket added to the system will be available when creating a new volume of the following type: Amazon S3, Ceph, Cloudian, EMC, Scality S3, Custom S3, Yandex, Alibaba.

It’s also possible to create new buckets via the CLI using the carbonio core doCreateBucket commands.

Bucket Paths and Naming#

Files are stored in a bucket according to a well-defined path, which can be customized at will in order to make your bucket’s contents easier to understand even on multi-server environments with multiple secondary volumes:

/Bucket Name/Destination Path/[Volume Prefix-]serverID/
  • The Bucket Name and Destination Path are not tied to the volume itself, and there can be as many volumes under the same destination path as you wish.

  • The Volume Prefix, on the other hand, is specific to each volume and it’s a quick way to differentiate and recognize different volumes within the bucket.

Amazon S3 Tips#

Bucket#

Storing your secondary Carbonio volumes on Amazon S3 doesn’t have any specific bucket requirements, but we suggest that you create a dedicated bucket and disable Static Website Hosting for easier management.

User#

To obtain an Access Key and the related Secret, a Programmatic Access user is needed. We suggest that you create a dedicated user in Amazon’s IAM Service for easier management.

Rights Management#

In Amazon’s IAM, you can set access policies for your users. It’s mandatory that the user of your Access Key and Secret has a set of appropriate rights both on the bucket itself and on its contents. For easier management, we recommend granting full rights as shown in the following example.

Example structure of user’s permission
{
    "Version": "[LATEST API VERSION]",
    "Statement": [
        {
            "Sid": "[AUTOMATICALLY GENERATED]",
            "Effect": "Allow",
            "Action": [
                "s3:*"
            ],
            "Resource": [
                "[BUCKET ARN]/*",
                "[BUCKET ARN]"
            ]
        }
    ]
}

Warning

This is not a valid configuration policy. Don’t copy and paste it into your user’s settings as it won’t be validated.

If you only wish to grant minimal permissions, change the Action section to:

"Action": [
                "s3:PutObject",
                "s3:GetObject",
                "s3:DeleteObject",
                "s3:AbortMultipartUpload",
                "s3:ListBucket"
              ],

The bucket’s ARN is expressed according to Amazon’s standard naming format: arn:partition:service:region:account-id:resource. For more information about this topic, please see Amazon’s documentation.

Bucket Paths and Naming#

Files are stored in a bucket according to a well-defined path, which can be customized at will to make your bucket’s contents easier to understand (even on multi-server environments with multiple secondary volumes):

/Bucket Name/Destination Path/serverID/

The Bucket Name and Destination Path are not tied to the volume itself, and there can be as many volumes under the same destination path as you wish.

The Volume Prefix, on the other hand, is specific to each volume and it’s a quick way to differentiate and recognize different volumes within the bucket.

Infrequent Access Storage Class#

Carbonio Storage is compatible with the Amazon S3 Standard - Infrequent access storage class and will set any file larger than the Infrequent Access Threshold value to this storage class as long as the option has been enabled on the volume.

See also

The official Amazon S3 documentation on Infrequent Access

Intelligent Tiering Storage Class#

Carbonio Storage is compatible with the Amazon S3 - Intelligent Tiering storage class and will set the appropriate Intelligent Tiering flag on all files, as long as the option has been enabled on the volume.

See also

The official Amazon S3 documentation on Intelligent Tiering

Item Deduplication#

What is Item Deduplication#

Item deduplication is a technique that allows you to save disk space by storing a single copy of an item and referencing it multiple times instead of storing multiple copies of the same item and referencing each copy only once.

This might seem like a minor improvement. However, in practical use, it makes a significant difference.

Item Deduplication in Carbonio#

Item deduplication is performed by Carbonio at the moment of storing a new item in the Current Primary Volume.

When a new item is being created, its message ID is compared to a list of cached items. If there is a match, a hard link to the cached message’s BLOB is created instead of a whole new BLOB for the message.

The dedupe cache is managed in Carbonio through the following config attributes.

zimbrarefDedupeMessagesSentToSelf

Used to set the deduplication behavior for sent-to-self messages:

<attr id="144" name="|carbonio|PrefDedupeMessagesSentToSelf" type="enum" value="dedupeNone,secondCopyifOnToOrCC,dedupeAll" cardinality="single"
optionalIn="account,cos" flags="accountInherited,domainAdminModifiable">
  <defaultCOSValue>dedupeNone</defaultCOSValue>
  <desc>dedupeNone|secondCopyIfOnToOrCC|moveSentMessageToInbox|dedupeAll</desc>
</attr>

zimbraMessageIdDedupeCacheSize

Number of cached Message IDs:

<attr id="334" name="|carbonio|MessageIdDedupeCacheSize" type="integer" cardinality="single" optionalIn="globalConfig" min="0">
  <globalConfigValue>3000</globalConfigValue>
  <desc>
    Number of Message-Id header values to keep in the LMTP dedupe cache.
    Subsequent attempts to deliver a message with a matching Message-Id
    to the same mailbox will be ignored.  A value of 0 disables deduping.
  </desc>
</attr>

zimbraPrefMessageIdDedupingEnabled

Manage deduplication at account or COS-level:

<attr id="1198" name="|carbonio|PrefMessageIdDedupingEnabled" type="boolean" cardinality="single" optionalIn="account,cos" flags="accountInherited"
 since="8.0.0">
  <defaultCOSValue>TRUE</defaultCOSValue>
  <desc>
    Account-level switch that enables message deduping.  See zimbraMessageIdDedupeCacheSize for more details.
  </desc>
</attr>

zimbraMessageIdDedupeCacheTimeout

Timeout for each entry in the dedupe cache:

<attr id="1340" name="zimbraMessageIdDedupeCacheTimeout" type="duration" cardinality="single" optionalIn="globalConfig" since="7.1.4">
  <globalConfigValue>0</globalConfigValue>
  <desc>
    Timeout for a Message-Id entry in the LMTP dedupe cache. A value of 0 indicates no timeout.
    zimbraMessageIdDedupeCacheSize limit is ignored when this is set to a non-zero value.
  </desc>
</attr>

Item Deduplication and Carbonio Storage#

The Carbonio Storage features a doDeduplicate operation that parses a target volume to find and deduplicate any duplicated item.

Doing so you will save even more disk space, as while Carbonio’s automatic deduplication is bound to a limited cache, Carbonio Storage’s deduplication will also find and take care of multiple copies of the same email regardless of any cache or timing.

Running the doDeduplicate operation is also highly suggested after a migration or a large data import in order to optimize your storage usage.

Running a Volume Deduplication#

Via the CLI

To run a volume deduplication through the CLI, use the carbonio powerstore doDeduplicate command.

zextras$ carbonio powerstore doDeduplicate *volume_name* [param \
VALUE[,VALUE]]

Parameter List

NAME

TYPE

EXPECTED VALUES

DEFAULT

volume_name (M)

String[,..]

dry_run (O)

Boolean

true|false

false

(M) == mandatory parameter, (O) == optional parameter

Usage Example

zextras$ carbonio powerstore doDeduplicate secondvolume

Starts a deduplication on volume secondvolume

To list all available volumes, you can use the carbonio getAllVolumes command.

doDeduplicate Stats#

The doDeduplicate operation is a valid target for the monitor command, meaning that you can watch the command’s statistics while it’s running through the carbonio powerstore monitor [operationID] command. Sample Output is:

Current Pass (Digest Prefix):  63/64
 Checked Mailboxes:             148/148
 Deduplicated/duplicated Blobs: 64868/137089
 Already Deduplicated Blobs:    71178
 Skipped Blobs:                 0
 Invalid Digests:               0
 Total Space Saved:             21.88 GB
  • Current Pass (Digest Prefix): The doDeduplicate command will analyze the BLOBS in groups based on the first character of their digest (name).

  • Checked Mailboxes: The number of mailboxes analyzed for the current pass.

  • Deduplicated/duplicated Blobs: Number of BLOBS deduplicated by the current operation / Number of total duplicated items on the volume.

  • Already Deduplicated Blobs: Number of deduplicated blobs on the volume (duplicated blobs that have been deduplicated by a previous run).

  • Skipped Blobs: BLOBs that have not been analyzed, usually because of a read error or missing file.

  • Invalid Digests: BLOBs with a bad digest (name different from the actual digest of the file).

  • Total Space Saved: Amount of disk space freed by the doDeduplicate operation.

Looking at the sample output above we can see that:

  • The operation is running the second to last pass on the last mailbox.

  • 137089 duplicated BLOBs have been found, 71178 of which have already been deduplicated previously.

  • The current operation deduplicated 64868 BLOBs, for a total disk space saving of 21.88GB.

Advanced Volume Operations#

Carbonio Storage: More than Meets the Eye#

At first sight, Carbonio Storage seems to be strictly dedicated to HSM. However, it also features some highly useful volume-related tools that are not directly related to HSM.

Due to the implicit risks in volume management, these tools are only available through the CLI.

Volume Operations at a Glance#

The following volume operations are available:

doCheckBlobs: Perform BLOB coherency checks on one or more volumes.

doDeduplicate: Start Item Deduplication on a volume.

doVolumeToVolumeMove: Move all items from one volume to another.

getVolumeStats: Display information about a volume’s size and number of thereby contained items/blobs.

doCheckBlobs

CLI full reference
zextras$ carbonio powerstore doCheckBlobs *start* [param \
VALUE[,VALUE]]

Parameter List

NAME

TYPE

EXPECTED VALUES

DEFAULT

action (M)

String

start

volumes (O)

String[, …]

message1,hsm[, …]

mailbox_ids (O)

Integer[, …]

2,9,27

missing_blobs_crosscheck (O)

Boolean

true|false

true

traced (O)

Boolean

true|false

false

fix_incorrect_compre ssed_digests (O)

Boolean

true|false

false

missing_blob_delete_item (O)

Boolean

true|false

false

check_digests (O)

Boolean

true|false

false

items (O)

String

files|all

all

(M) == mandatory parameter, (O) == optional parameter

Usage Example

zextras$ carbonio powerstore doCheckBlobs start

Perform a BLOB coherency check on all message volumes

Usage Example

zextras$ carbonio powerstore doCheckBlobs start volumes \
message1,hsm

Perform a BLOB coherency check on volumes message1 and hsm

Usage Example

zextras$ carbonio powerstore doCheckBlobs start mailbox_ids 2,9,27

Perform a BLOB coherency check on mailboxes 2,9 and 27

Usage Example

zextras$ carbonio powerstore doCheckBlobs start \
missing_blobs_crosscheck false

Perform a BLOB coherency check without checking on other volumes

Usage Example

zextras$ carbonio powerstore doCheckBlobs start traced true

Perform a BLOB coherency check, logging even the correct checked items

Usage Example

zextras$ carbonio powerstore doCheckBlobs start \
fix_incorrect_compressed_digests true

This option verifies if the digest (hash) of every object is correct and eventually fixes it

Usage Example

zextras$ carbonio powerstore doCheckBlobs start check_digests true

Verifies if the blob digests are correct

Usage Example

zextras$ carbonio powerstore doCheckBlobs start \
missing_blob_delete_item true

Remove entries from the database that are missing their blob file in the hsm volume

Volume names are case sensitive. Run zextras$ carbonio powerstore getAllVolumes for a complete list of the volumes.

Description and Tips

The doCheckBlobs operation can be used to run BLOB coherency checks on volumes and mailboxes. This can be useful when experiencing issues related to broken or unviewable items, which are often caused because either Carbonio cannot find or access the BLOB file related to an item or there is an issue with the BLOB content itself.

Specifically, the following checks are made:

  • DB-to-BLOB coherency: For every Item entry in Carbonio’s DB, check whether the appropriate BLOB file exists.

  • BLOB-to-DB coherency: For every BLOB file in a volume/mailbox, check whether the appropriate DB data exists.

  • Filename coherency: Checks the coherency of each BLOB’s filename with its content (as BLOBs are named after their file’s SHA hash).

  • Size coherency: For every BLOB file in a volume/mailbox, checks whether the BLOB file’s size is coherent with the expected size (stored in the DB).

Important

The old zmblobchk command is deprecated and replaced by carbonio powerstore doCheckBlobs on all infrastructures using Carbonio Storage module.

doDeduplicate

CLI full reference
zextras$ carbonio powerstore doDeduplicate *volume_name* [param \
VALUE[,VALUE]]

Parameter List

NAME

TYPE

EXPECTED VALUES

DEFAULT

volume_name (M)

String[,..]

dry_run (O)

Boolean

true|false

false

(M) == mandatory parameter, (O) == optional parameter

Usage Example

zextras$ carbonio powerstore doDeduplicate secondvolume

Starts a deduplication on volume secondvolume

doVolumeToVolumeMove

CLI full reference
zextras$ carbonio powerstore doVolumeToVolumeMove \
*source_volume_name* *destination_volume_name* [param \
VALUE[,VALUE]]

Parameter List

NAME

TYPE

EXPECTED VALUES

DEFAULT

source_volume_name (M)

String

destination_volume_name (M)

String

only_files_and_chats(O)

Boolean

true|false

false

read_error_threshold (O)

Integer

policy(O)

String

none

perform_deduplicate(O)

Boolean

true|false

false

overwrite_index_destination (O)

Boolean

true|false

false

(M) == mandatory parameter, (O) == optional parameter

Usage Example

zextras$ carbonio powerstore doVolumeToVolumeMove sourceVolume \
destVolume

Moves the whole sourceVolume to destVolume

Description and Tips

This command can prove highly useful in all situations where you need to stop using a volume, such as:

  • Decommissioning old hardware: If you want to get rid of an old disk in a physical server, create new volumes on other/newer disks and move your data there.

  • Fixing little mistakes: If you accidentally create a new volume in the wrong place, move the data to another volume.

  • Centralize volumes: Centralize and move volumes as you please, for example, if you redesigned your storage infrastructure or you are tidying up your Carbonio volumes.

Hint

Starting from version 3.0.10, Carbonio Storage can also move “Index” volumes.

getVolumeStats

CLI full reference
zextras$ carbonio powerstore getVolumeStats *volume_name* [param \
VALUE[,VALUE]]

Parameter List

NAME

TYPE

EXPECTED VALUES

DEFAULT

volume_name (M)

String

show_volume_size (O)

Boolean

true|false

false

show_blob_num (O)

Boolean

true|false

false

(M) == mandatory parameter, (O) == optional parameter

Warning

BE CAREFUL the show_volume_size and show_blob_num options are I/O intensive and thus disabled by default.

Usage Example

zextras$ carbonio powerstore getVolumeStats volumeName

Shows stats for the volume with name equal to volumeName

Description and Tips

This command provides the following information about a volume:

Name

Description

id

The ID of the volume

name

The Name of the volume

path

The Path of the volume

compressed

Compression enabled/disabled

threshold

Compression threshold (in bytes)

lastMoveOutcome

Exit status of the latest doMoveBlobs operation

lastMoveTimestamp

End timestamp of the latest doMoveBlobs operation

lastMoveDuration

Duration of the last doMoveBlobs operation

lastItemMovedCount

Number of items moved to the current secondary volume during the latest doMoveBlobs operation

bytesSaved

Total amount of disk space freed up thanks to deduplication and compression

bytesSavedLast

Amount of disk space freed up thanks to deduplication and compression during the latest doMoveBlobs operation

The show_volume_size and show_blob_num options will add the following data to the output:

Option

Name

description

show_volume_size

totSize

Total disk space used

show_blob_num

blobNumber

Number of BLOB files