Storage resiliance - how?

growse · 18 Jan 2011 at 10:33

Hi all,

I've got a smallish virtualized environment running vSphere 4.1 with storage provided over NFS via a single HP X1600 NAS (running Solaris). I'm starting to look at ways in which I can improve the resilience of this and remove any single points of failure.

I'm fairly sure I can sort out the resilience on the OS, host and networking level, but storage is something that's not obvious at the moment.

At the moment I'm considering buying another X1600, whacking fibre in everything and then using multipathing from VMware to the storage devices (you can't multipath NFS I don't think). However, it's not clear to me how you keep the data in sync between the two NAS units. Would I be better off using the other NAS as a hot-standby and just doing periodic ZFS exports from NAS1 to NAS2?

What are my options here?

matthab · 18 Jan 2011 at 13:30

Im not certain but I think some of the synology nas's allow for replication.

They have a very good and powerfull interface thoe so might be worth looking into them.

http://www.synology.com/enu/products/features/backup_server.php

Skidilliplop · 18 Jan 2011 at 13:52

It depends how elegant you want it. IDeally you'd want Byte level replication between the NAS boxes.

Personally i've not got much experience with NFS, but using iSCSI the way i'd do it in simple DIY terms would be to create volumes on both, mount them to the server and use drive mirroring between them to maintain perfect duplicates.
I'm not sure how your NFS mounts and if you can mirror them as a single logical drive, Cue NFS Gurus

Laser402 · 19 Jan 2011 at 11:07

A quick google gives: Click
Looks like you need to look at 'HP StorageWorks Storage Mirroring Software' for replication between the 2 X1600's

Besty · 19 Jan 2011 at 21:08

you could consider VM level replication, this could be cheaper and more efficient than going down the full replicated storage route.

it has its dis-advantages, it depends on how slick you want it to be.

the more expensive enterprise level software is Platespin Protect, there are others on the market which do a similar job for less.

growse · 20 Jan 2011 at 12:53

Thanks for the responses. On the VM replication front, would that be a case of keeping two identical VMs in fault tolerance but hosted on different datastores?

Knubje · 20 Jan 2011 at 16:29

growse said:
Thanks for the responses. On the VM replication front, would that be a case of keeping two identical VMs in fault tolerance but hosted on different datastores?

Essentially that is what it does.

I use vReplicator software where I am, which is from Quest Software (formerly vizion core).

It replicates your machine on a schedule of your choosing to alternate data store/host. There is a time limit though, I believe the smallest increment is 5 minutes (and will depend on your backup servers resources). This is more than adequate where I am but obviously not so much where the RTO of a business is seconds rather than minutes.

It is quite useful as a backup tool and has got me out of trouble on a few occasions so has been worth it for us. If your SAN went down, you would have a copy of your production VM's from 15 minutes ago sat on your other one ready for use. If used in conjunction with vMotion or something similar it can definitively do a job.