Best practice configuration of a RS409 for ESX 4

[baker]

Is there a best practice document that provides direction on configuring the RS409 NAS for connectivity and sufficient throughput to support virtual configurations and virtual hard drive files so the NAS can be used with ESX 4.
I would prefer to use iSCSI since I have multiple Physical ESX hosts.

baker-

[rs407]

I have done som testing with ESXI and Synology RS407 (a old NAS).
See viewtopic.php?f=148&t=18133
In the RS407 the ISCSI performance is to low on writes, it cant be used for storage for ESXI.

Next time we need low-end storage we will most likley try the new RS810 (with extra memory), it will be intresting to see the performance compared to our mid-range disk arrays.

We will use NFS and not ISCSI between ESXI and Synology for the following reasons:
1.Simplicity
Only one volume for all VM that will use the synology storage, with ISCSI you get several 1TB* LUNs where you can place your VM:s
You can use VMFS extent to group LUNs to bigger disks but we only use that to make smaller LUNs to 1TB LUNs (see argument 3 below)
*A LUN in ESXI 3.5 can be max 2TB

2.Reduce waste
With one big volumes over NFS your disk "waste" will be smaller then with 1-2TB LUNS.
Ex: a 6TB NFS volume (4x2TB disk) or 6 ISCSI volumes at 1TB, you will not be able to use every byte of the LUN.
With one volume you will only lose once, with 6 volumes you .....

3.Allocation of VM
With NFS every VM gets its own "handle" to its files on the NFS server, the NFS server handles the coordination between diffrent VM files.
High-end diskarrays manufactures like Netapp are primaiy used as advanced NFS servers,they have support for ISCSI but NFS are better.
With ISCSI you have to consider size of LUN and number of VM per LUN to avoid "disklocks"

4.Performance
NFS have in my testing with RS407 better performance.
Dont forget to make your volume "asynchronius = YES" in "NFS privileges" (requires DSM 3.0)

But thats only my opinion
/R

[stan.gobien]

Thanks a lot for the async = yes option. NFS performance was very slow on my RS409 in combination with ESXi 4.
ISCSI was fast but can't be backedup by the netbackup. Now with async, NFS is fast aswell!

[rs407]

Hi,

Here are some argument for ISCSI over NFS (Im agumenting against myself )
With the release of ESXI 4.1 and the "Storage I/O Control" feature that work on FC and ISCSI but not NFS seems to be great!
But I have to test i first....
If Storage I/O Controll is as good as promised then it by itself arguments for ISCSI instead of NFS.
With "Storage I/O Control" its a equal, ISCSI for handling load, NFS for simplicity.
One other argument for ISCSI whould be ISCSI hardware offload for 10G, but then we not talking "low cost" virtualization enviroments.

http://www.vmware.com/files/pdf/techpaper/VMW-Whats-New-vSphere41-Performance.pdf
http://www.vmware.com/files/pdf/techpaper/VMW-Whats-New-vSphere41-Storage.pdf

Its a ever changing world...

Edit 2011-06-30
Storage I/O Control seems to work and bring stability to vSphere, however we cant use it in our existing setup.
The reason is that we have a mix of "vSphere standard" and "VSphere Enterprise Plus" licens in our vmware setup (22 hostes with 5 standard and the rest E+) that share the same datastores (55 datastores, two NFS and the rest FC LUN or ISCSI LUN).
The "standard" edition dosnt support "Storage I/O Control" so the "Standard" edition cant share a datastore with a "Enterprise Plus" with "Storage I/O Control" enabled.

To enable "Storage I/O Control" we need to separate the diffrent vSphere editions on different datastores.
So i practice we cant use "Storage I/O Control" without a lot of reconfiguration and adding more storage.

And that gives NFS the advantage again, for all editions except E+ and in enviroment with mixed editions.

Its a always changing world...IRL

/R