We've got a wide variety of HP servers as clients, running CentOS 5  
and OpenISCSI, talking to three LeftHand Networks NSM2120s (which are  
essentially rebranded HP DL320s servers with their custom OS loaded on  
them).

We thought it was a switching issue as well at first, where we had a  
pair of Force10 S50Ns that I absolutely hated (still do, for lots of  
reasons), but after replacing them with a pair of Cisco 3750Gs, I can  
say that for as much as I hate the F10s, they weren't the cause of  
this particular problem.

D

On Oct 30, 2008, at 4:18 PM, Joshua Nichols wrote:

> What hardware are you using?  A colleague of mine just spent a few
> weeks working to get peak performance out of some Dell md3000Is to
> keep up with the needs of a client of his.  Let's call them "an online
> media company."
>
> My point is that baseline performance is determined so much by the
> specific hardware, that what works to get an md3k cruising may prove
> absolutely useless in your setup.
>
> Also, the switch is probably a bigger factor in overall speed than one
> might guess at first...
>
>
> On Oct 30, 2008, at 3:07 PM, Derek J. Balling wrote:
>
>> I'm trying to determine what's a good "baseline performance level"  
>> for
>> my iSCSI SAN. We're seeing what we consider to be suboptimal
>> performance, but I'm not sure where to pin the blame down -- or even
>> if there IS any blame, maybe our metrics are in line with what people
>> are getting for Linux iSCSI clients. Who knows.
>>
>> What I'm seeing is that - if I use IOMeter as my performance testing
>> tool (which seems to be fairly common in SAN testing), I can only get
>> about 300-400 read IOP/s, with total throughput of about 10MB/s.
>> Contrarily if I let IOmeter test the local disk, it's 6x faster (1900
>> IOP/s, 60MB/s)
>>
>> Now that SEEMS awful low to us. There's a number of factors that  
>> might
>> be contributing to it (it could be a network issue, it could simply  
>> be
>> that the SAN hardware itself is saturated for IOPS -- I tend towards
>> that last, but unfortunately, the SAN hardware we're using has
>> NO(!!!!) means of letting me determine what the current IOPS are on
>> the SAN disks themselves.... crazy-talk, I tell you).
>>
>> Anyone out there want to share their metrics?
>>
>> Cheers,
>> D
>>
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