Replication

I’ve been stuck with this error recently on a Celerra manager device : DpRequest_Max_VS_SuspendedCheckpointsReached

This can sometimes happen when a filesystem is held during a replication task. To check what filesystems are currently being replcated run the following command;

nas_replicate -info -all

Either wait until the replication has completed - check status. Or temporary stop the replication task (stop it from the source side if possible).

Check this link for a great script to monitor changes made to a virtual machine via the vmware CBT API. This is perfect for finding culprit machines that are generating a lot of replication traffic if you are replicating over a WAN.

http://www.vmguru.com/index.php/articles-mainmenu-62/scripting/105-using-powershell-to-track-block-change-sizes-over-time

If you have some disks on a virtual machine you don’t want this script to capture then just set them as independent disks (so no snapshots can take place). This is handy if you have your windows page file on a separate disk that you don’t want to be measured as a part of the CBT changes.

I’ve been working through a SRM setup and have been looking at ways to optimize the amount of traffic that is sent over the WAN. The first obvious move is to move your vmware swap files off the replicated LUNS.

Another way is to reduce the sync window. i.e. how often is yoru replication technology trying to keep the source and destination in sync? – Increasing this window can sometimes help you out. But that all depends on your delta’s.