Thanks Amos. According to AWS docs:
> I/O size is capped at 256 KiB for SSD volumes > When small I/O operations are physically contiguous, Amazon EBS attempts to merge them into a single I/O up to the maximum size. For example, for SSD volumes, a single 1,024 KiB I/O operation counts as 4 operations (1,024÷256=4), while 8 contiguous I/O operations at 32 KiB each count as 1operation (8×32=256). However, 8 random I/O operations at 32 KiB each count as 8 operations. Each I/O operation under 32 KiB counts as 1 operation. So it's not so easy to figure out correlation between squid swap ops and AWS EBS ops. What I see from here is: * Multiple squid swap in or swap out ops reading/writing contiguous blocks could be merged into one 256KB IO operation. * Random squid operations could be handled as single 32KB IO operation. On Thu, Jan 18, 2018 at 3:20 PM, Amos Jeffries <squ...@treenet.co.nz> wrote: > On 19/01/18 12:04, Ivan Larionov wrote: > >> Thank you for the fast reply! >> >> read_ops and write_ops is AWS EBS metric and in general it correlates >> with OS-level reads/s writes/s stats which iostat shows. >> >> So if I understand you correctly max-swap-rate doesn't limit disk IOPS >> but limits squid swap ops instead and every squid operation could in theory >> use more than 1 disk IO operation. This means we can't really say "limit >> swap ops to 1500 because our disk can handle 1500 iops" but should figure >> out the number after testing different values. >> >> Ok, I suppose I'll just do what Rock documentation says – will test >> different values and figure out what works for us. >> >> > > If you know what the OS level IOP size is (eg usually 4KB) and the Squid > rock IOP size Alex mentioned of 32KB. That should give you a number to > divide the disk IOPS limit you want with to get a rough estimate for the > appropriate Squid setting. > > The tuning bit is just to see how much variance from that is caused by > your traffic objects being different from the 32KB slot size. > > > Amos > > _______________________________________________ > squid-users mailing list > squid-users@lists.squid-cache.org > http://lists.squid-cache.org/listinfo/squid-users > -- With best regards, Ivan Larionov.
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