I am not sure that's really true. ALL writes are going to be "sequential" if they can - the filer writes to NVRAM not disk directly. So the AFAIK the writes are always as sequential as they can be*
Reads are cached like crazy, esp when PAM/FlashCache etc.
*Generally when someone says they want to know they are looking for bottlenecks. I stand by statit as a tool for this since you are seeing how each disk is working. You might not know exactly what's causing the issue but it's good data to know what is going on at the aggregate level (which is what he is asking about) and the RG level (which is where the performance for an aggregate is going to be determined).
Disk Statistics (per second) ut% is the percent of time the disk was busy. xfers is the number of data-transfer commands issued per second. xfers = ureads + writes + cpreads + greads + gwrites chain is the average number of 4K blocks per command. usecs is the average disk round-trip time per 4K block.
*Jeremy Page* | Senior Technical Architect | *Gilbarco Veeder-Root, A Danaher Company* *Office:*336-547-5399 | *Cell:*336-601-7274 | *24x7 Emergency:*336-430-8151 ------------------------------------------------------------------------ On 01/16/2014 04:56 PM, Jeff Mohler wrote:
Statit will get you the AMALGAMATED workload to disks on writes, not individual IOs. There's nothing there.
On reads..sure, I can see that. The un-cached client read IO requests+readahead..but still an amalgamated result aggregate wide since you have no data locality to be very precise about it.
On Thu, Jan 16, 2014 at 1:32 PM, Jeremy Page <jeremy.page@gilbarco.com mailto:jeremy.page@gilbarco.com> wrote:
statit will give it to you /per disk / On 01/16/2014 04:25 PM, Martin wrote:Hi, I'm trying to characterize the workload on our Netapp Filer running VMware over NFS and iSCSI for benchmarking purposes using IOmeter. Is it possible to determine what the percentage random sequential distribution the workload is on a Filer e.g from a perfstat? I've looked at vscsiStats but that is only per VM and not for the aggregate workload on the Filer. -- View this message in context: http://network-appliance-toasters.10978.n7.nabble.com/Random-Sequential-measurement-on-Filers-tp25474.html Sent from the Network Appliance - Toasters mailing list archive at Nabble.com. _______________________________________________ Toasters mailing list Toasters@teaparty.net <mailto:Toasters@teaparty.net> http://www.teaparty.net/mailman/listinfo/toastersPlease be advised that this email may contain confidential information. If you are not the intended recipient, please notify us by email by replying to the sender and delete this message. The sender disclaims that the content of this email constitutes an offer to enter into, or the acceptance of, any agreement; provided that the foregoing does not invalidate the binding effect of any digital or other electronic reproduction of a manual signature that is included in any attachment. _______________________________________________ Toasters mailing list Toasters@teaparty.net <mailto:Toasters@teaparty.net> http://www.teaparty.net/mailman/listinfo/toasters--
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