EMC Sym DMX / FA Port Flag SPC-2

[AWo]

Has anybody made some experiences regarding storage performance between a FA port with SPC-2 enabled and without?

I'm facing some performance problems but the analysis has shown that "everybody" feels fine (not latencys, high cache hit rates, no high utilizations on FC switch ports, FA ports, disks, etc), but we're fare away from what is possible (compared to a direct attached physical system; testing was done with one single guest on one ESX host).

One thing I saw is that the FA port flag settings are not according to what VMware and EMC would like to have for ESX 3.x (no SPC-2, no SC3). And as far as I know the SPC-2 flag enables an optimized SCSI command set.

(All other things like load distribution over multipathing, vmdk distribution over many LUN's etc. are already done and that has raised the performance a little bit.)

AWo

VCP / vEXPERT 2009

[AWo]

After migration all LUN's to a FC-DA with the suggested settings I was able to gain about 4-6 MB/s more performance.
AWo

VCP / VMware vEXPERT 2009

[ThompsG]

Evening,

This is good to know. We are currently implementing a pair of DMX4's in our environment.

Our implementors have recommended using RAID6 for our VMware environment. We feel that things are slow compared to what we had before however latency, queue lengths, etc are still low. Also users have not complained yet, so all is good. We are mainly basing the feeling on speed tests we have run independantly. Thought you may have found something that could be impacting our speed but, alas, we have the SPC-2 flag set on our directors already.

Before others add comments about RAID6, we are well aware that RAID6 has a much slower write speed than RAID5, but the sales people said the huge cache of the DMX would fix that

Kind regards

[AWo]

Do you have access to Powerlink?

Look for "H4116-enabling-spc2-compl-emc-symmetrix-dmx-vmware-envnmt-wp.pdf".

At VMware look at http://www.vmware.com/pdf/vi3_35/esx_3/r35/vi3_35_25_san_cfg.pdf, page 57.

I took the following actions to distribute the load and to get more performance:

1. Distributed the system drives (most of the time holding th eguest swap file) equally over all LUN's

2. Manually configured load balancing over the two paths available to each LUN

3. Configured the FA ports as noted in th eabove documents

After all these actions I'm very close to the performance of a single physical server attached to the SAN (2 - 3 MB/s slower at an average).

AWo

VCP / VMware vEXPERT 2009

[ThompsG]

Evening,

Yes I do have access to PowerLink and will look up the article you have suggested. Suspect we have already read it but would not hurt to look again.

We are already doing the manual load balancing of our LUNs accross 4 FA's, so pretty sure we have this covered.

I'll do the reading tomorrow and report back if we see anything of use. Thanks for your help.

Kind regards.