P4000 VSA RemoteCopy

[J78920]

Hi 

I've setup a scheduled remotecopy snapshot of my volume from my primary management group, this copies to a test VSA that runs internally on our network. The idea is ito test the size of the incremental snapshots before we try and replicate this over the WAN link. 

I have discovered that the incremental snaps are way bigger than expected. I have a volume that is approximately 500GB and I have set an interval of 3 hours between snaps for testing and the reported size is over 600MB everytime! We know that our data is not changing this much in that time, the snaps are in excess of this over periods of no activity. 

Is this normal as I was under the impression that it's incremental block changes that are copied? 

[Mike_Povall]

Hi,

You need to check for things like anti virus applications running scheduled scans of the volume as I have seen Sophos cause situations like this in the past where the scanned file would be 'touched' by the AV.

Regards, Mike.

[oikjn]

/end rant

As for the OP.  Are you 100% sure there is no activity on these volumes?  Pagefiles?  Temp drives?  log files?  600MB in three hours isn't too crazy.  If there are temp files or pagefiles, you might find that about 600MB changes in about 30 minutes and then the same 600MB cahnges every 30 muinutes or so and if you extended your snapshot interval from 3 hours to 6 hours you would not see a linear growth rate of your snapshots. 

If you really want to test the SAN/iQ snapshot performance I would suggest setting up a dedicated LUN to test the snapshot performance and then do very controlled changes to monitor how the system handled it...  then you go to try the step you took and see what your actual change rate is and then you can know if you should tweak your setup to optimize for snapshot growth.