
phigmov at gmail
Oct 6, 2009, 1:14 PM
Post #8 of 8
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Thanks for all the advice - thanks to Romeo Theriaults awesome tool I'll run some stats over time and see how things look. I'll probably give Logicmonitor a quick look and see how it compares to DFM. Cheers, Raj. On 10/7/09, Kevin M. Parker <kevin [at] theparkerz> wrote: > Raj, > I'll share knowledge I've received specific to NFS environments (and > this may be specific to VMware over NFS - sorry I can't confirm). The > way I understand it is that clients start experiencing negative > performance after 20ms disk latency. I do not know if that same latency > applies to iSCSI traffic. > > As it relates to the disks making up your aggregates, I can offer the > following numbers as they relate to disk IOPS, which is also somewhat > related to the original request in this thread. Numbers below are the > IOPS that disk can sustain before experiencing a >= 20ms delay. > FC [at] 10KRP: 120IOPS > FC [at] 15KRP: 220IOPS > SATA: 40IOPS > > I had looked on NOW for this type info but did not come up w/anything > quickly - perhaps you could reach out to your SE. > > -/- > Kevin Parker > 919.521.8413 > http://theparkerz.com > Blackle.com - Saving energy one search at a time. > > > -----Original Message----- > From: owner-toasters [at] mathworks [mailto:owner-toasters [at] mathworks] > On Behalf Of Raj Patel > Sent: Monday, October 05, 2009 12:59 AM > To: Romeo Theriault > Cc: Maxwell Reid; vera.lee [at] avagotech; Milazzo Giacomo; > toasters [at] mathworks > Subject: Re: High CPU utilizations and file I/O > > As a matter of interest how much latency is to much (I know, how many > angels can you fit on a pinhead) ? > > We've had a few DBA types come and comment on long SQL queue lengths > associated with disk i/o - the SQL luns are connected via iSCSI. > > As far as the end user is concerned performance seems fine for things > like SharePoint and CRM. Even Exchange. However a few apps with high > i/o (mail archiving to database and SCOM which seems to thrash the > database) do seem to suffer a little in terms of slow response time. > > Do people have tips for optimising iSCSI performance (targets are ESX > servers, Exchange on physical hardware and SQL on a mix of physical > and virtual servers) ? > > What key counters should I keep an eye on ? > > Fibre Channel is still prohibitively expensive plus 10GbE seems very > promising and more pervasive than a few years ago. > > Cheers, > Raj. > > On 10/3/09, Romeo Theriault <romeotheriault [at] gmail> wrote: >>> >>> I think everyone would be interested in the updated version! >>> >> >> Great! Ok, I'll put up the version that can also filter on aggregates > on >> Monday. I hadn't put it up earlier mainly because it takes a bit more > setup >> to get working. I used the netapp perl api to access the aggregate >> information so it also requires a user account with the appropriate > api >> permissions and the associated netapp perl api modules. I just haven't >> gotten around to figuring out if I can legally bundle the netapp perl >> modules and just generally putting it in a easily usable package for > the >> general public. I'll try to figure out the details on monday and see > what I >> can get out, with or without the netapp modules. >> >> -- >> Romeo Theriault >> System Administrator >> Information Technology Services >> >
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