Re: [ceph-users] RADOS Bench strange behavior

2013-07-10 Thread Gregory Farnum
On Wed, Jul 10, 2013 at 12:38 AM, Erwan Velu wrote: > Hi, > > I've just subscribe the mailing. I'm maybe breaking the thread as I cannot > "answer to all" ;o) > > I'd like to share my research on understanding of this behavior. > > A rados put is showing the expected behavior while the rados bench

Re: [ceph-users] RADOS Bench strange behavior

2013-07-10 Thread Erwan Velu
Hi, I've just subscribe the mailing. I'm maybe breaking the thread as I cannot "answer to all" ;o) I'd like to share my research on understanding of this behavior. A rados put is showing the expected behavior while the rados bench doesn't even with a concurrency set to one. As a new comer,

Re: [ceph-users] RADOS Bench strange behavior

2013-07-09 Thread Sebastien Han
Hrm!  Were you using 4MB of data with rados put?  Also, I don't know how much extra latency running "rados put" would add from start to finish. Is it slower than RADOS bench when you loop it?  It may not show much concurrency if the writes on the OSDs are finishing quickly and waiting on the next o

Re: [ceph-users] RADOS Bench strange behavior

2013-07-09 Thread Mark Nelson
On 07/09/2013 06:47 AM, Sebastien Han wrote: Hi Mark, Yes write back caching is enable since we have a BBU. See the current cache policy of the controller: WriteBack, ReadAheadNone and Direct. FYI, both journal and filestore are stored on the same disks, thus sd*1 is the journal and sd*2 is the

Re: [ceph-users] RADOS Bench strange behavior

2013-07-09 Thread Sebastien Han
Hi Mark,Yes write back caching is enable since we have a BBU. See the current cache policy of the controller: WriteBack, ReadAheadNone and Direct.FYI, both journal and filestore are stored on the same disks, thus sd*1 is the journal and sd*2 is the filestore.In order to give you a little bit more a

Re: [ceph-users] RADOS Bench strange behavior

2013-07-09 Thread Mark Nelson
On 07/09/2013 03:20 AM, Sebastien Han wrote: Hi all, While running some benchmarks with the internal rados benchmarker I noticed something really strange. First of all, this is the line I used to run it: $ sudo rados -p 07:59:54_performance bench 300 write -b 4194304 -t 1 --no-cleanup So I wan

[ceph-users] RADOS Bench strange behavior

2013-07-09 Thread Sebastien Han
Hi all,While running some benchmarks with the internal rados benchmarker I noticed something really strange. First of all, this is the line I used to run it:$ sudo rados -p 07:59:54_performance bench 300 write -b 4194304 -t 1 --no-cleanupSo I want to test an IO with a concurrency of 1. I had a look