2010-07-19 01:43 PM
So we had a bunch of flexible volumes, all mounted via nfs:
In order to deduplicate them on DataONTAP 7.3.3, we jammed them all into a single volume:
2010-07-20 11:20 AM
Just 2 quick thoughts:
Hope that helped.
2010-07-20 01:08 PM
Indeed, you have to choose.
But how big are your old volumes (qtrees). Because I think that when they are 500 GB - 1 TB, that it make sense to make separate volumes.
But why do you want qtrees? Do you have separated backup retention policies? We use one backup policy for all our VM's: not that we need the same for all the VM's but it's easy and than you can use snapmirror.
2010-07-20 01:26 PM
We're using qtree quotas -- nonetheless when the volume got accidentally filled each vm got the lesser of the qtree quota or the available space in the volume. Thus they all failed at once. Separate volumes would be more isolated.
We're using volume snapmirror.
Each of these qtrees consists of thousands of files (these are Xen VM's with thousands of nfs files, not a single virtualized container ala VMWare).
2010-07-20 01:35 PM
We want qtrees because otherwise we get 0% dedupe. Though, at 16% dedupe, it hardly seems worth it:
netapp0a> df -ih /vol/xen_vms/
Filesystem iused ifree %iused Mounted on
/vol/xen_vms/ 8309590 13826990 38% /vol/xen_vms/
netapp0a> df -h /vol/xen_vms/
Filesystem total used avail capacity Mounted on
/vol/xen_vms/ 254GB 154GB 99GB 61% /vol/xen_vms/
/vol/xen_vms/.snapshot 0KB 380MB 0KB ---% /vol/xen_vms/.snapshot
netapp0a> df -sh /vol/xen_vms/
Filesystem used saved %saved
/vol/xen_vms/ 154GB 30GB 16%
#Auto-generated by setup Wed Oct 17 21:40:24 GMT 2007
"/vol/xen_vms/fisheye.svc" tree 6291456K - 6291456K 6291456K -
"/vol/xen_vms/cacti.svc" tree 4194304K - 4194304K 4194304K -
"/vol/xen_vms/xfer.util" tree 8388608K - 8388608K 8388608K -....
Each of these is a Xen VM running either Debian Etch or Debian Lenny.
2010-07-20 10:42 PM
Your dedupe ratio seems rather low. What OS are your VMs are you running? What is your dedupe schedule?
That is probably because he does not have that many VMs in the volume (150 GB is not much). And perhaps not all the same OS.
2010-07-21 04:39 AM
I would make sure that you have block alignment between your guest filesystems, your partition table inside the VMDK, and the 4K boundry of WAFL.
I would also take a look at the placement of your guest OS swap and your VM swap.
Did you clone your Etch and Lenny installs or is every install fresh from media?
2010-07-21 08:58 AM
There is no, as far as I can tell, block alignment possible for a nfs volume. (note: vmware is not installed).
Swap is on local disk.
Each VM is a copy of a prior one (not always the same prior one, but definitely a prior one).