Zimbra Suite Plus/Zimbra HSM Plus/doMoveBlobs

Zimbra HSM Plus - doMoveBlobs

The doMoveBlobs operation of Zimbra HSM Plus

The doMoveBlobs is the heart of the Zimbra HSM Plus Modules.

It's duty is to move items between the Current Primary Store and the Current Secondary Store according to the proper HSM policy.

The move is performed by a transactional algorythm, so should an error occour during one of the steps of the operation a rollback would take place and no change will be made to the data.

Once Zimbra HSM Plus identifies the items to be moved, the following steps are performed:

Create a copy of the Blob to the Current Secondary Store.
Update the Zimbra Database in order to notify Zimbra of the new position of the item.
Delete the original Blob from the Current Primary Store.

What will be moved

Basically, every item that complies to the specified HSM policy.

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 and containing an attachment.

Policy order

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

This mean 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 containing one or more attachments, will have the same final result while the execution time will probably be slightly higher (or much higer, depending on the number and size of the emails in the server).

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

Viceversa, 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 on 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.

Zimbra HSM Plus gives you 3 different options to do so:

via the Zimbra Suite Plus Administration Zimlet
via the Zimbra Suite Plus CLI
through Scheduling

Apply the HSM Policy via the Zimbra Suite Plus Administration Zimlet

In order to apply the HSM Policy via the Zimbra Suite Plus Administration Zimlet:

Log into the Zimbra Administration Console
Click the "Zimbra HSM Plus" entry on the Zimbra Suite Plus Administration Zimlet
Click the "Apply Policy" button

Apply the HSM Policy via the Zimbra Suite Plus CLI

In order to apply the HSM Policy via the Zimbra Suite Plus CLI, run the following command as the 'zimbra' user:

 zxsuite powerstore doMoveBlobs

Apply the HSM Policy through Scheduling

In order to schedule a daily execution of the "doMoveBlobs" operation:

Log into the Zimbra Administration Console
Click the "Zimbra HSM Plus" entry on the Zimbra Suite Plus Administration Zimlet
Enable the scheduling by selecting the "Enable Policy Application scheduling" button
Select the hour to run the operation under "Policy Application scheduled for:"

doMoveBlobs Stats and Info

Informations about disk space savings, operation performances and more are available by clicking the "Stats" button under the "Secondary Volumes" list in the Zimbra HSM Plus tab of the Zimbra Suite Plus Administration Zimlet.

Aug 25, 2016 - Know more »