Allan, This can be my problem. I see some fallbacks in debug log. Do you know if there is some development in progress or workaround for this case ? Thanks,
2015-03-17 18:38 GMT-03:00 Alan Carroll <[email protected]>: > One thing to check for is (1) large objects in the cache and (2) > multi-range requests. In this case ATS will read the entire object and > filter out that parts that aren't in the range requests. The standard range > acceleration only works for single range requests. Every object resides on > a single disk so if this is a specific object you would see this heavy read > only on that disk. There is a debug message for this but unfortunately it's > "http_trans" which generates *a lot* of output. If you're willing to do a > minor tweak of the source, look in HttpSM.cc for the line reading "Unable > to accelerate range request" and change the tag from "http_trans" to > something more specific such as "http_trans_range" and then use that as the > debug tag. > > This may not be the problem, but it is worth taking a look. > > > > On Tuesday, March 17, 2015 4:12 PM, Tommy Lee <[email protected]> > wrote: > > > Hi everybody, > > We are using ATS 4.2.1 with raw disks config and volume and hosting > configs enabled. > And we're experiencing strange high read rates randomly at one disk. > We use LSI Megaraid configured with RAID 0 ( Write back, Read Ahead, > Cached IO and write cache, strip size 1MB ). > My question is: There is someway to see with debug tags what's is going > on ? > > ATS can be performing some maintenance tasks that randomly read disk at > higher rates ? > > IOPs goes up to 450 and read speed reaches (90 MB/s) staying for 30~50 > seconds and then goes back to normal. > > I would thank if anyone can give some direction where to search for this > debug inside the code. > > > Best regards, > > > >
