Re: [zfs-discuss] Impact of an enterprise class SSD on ZIL performance

2010-02-05 Thread Miles Nordin
pr == Peter Radig pe...@radig.de writes: ls == Lutz Schumann presa...@storageconcepts.de writes: pr I was expecting a good performance from the X25-E, but was pr really suprised that it is that good (only 1.7 times slower pr than it takes with ZIL completely disabled). So I will use

Re: [zfs-discuss] Impact of an enterprise class SSD on ZIL performance

2010-02-05 Thread Bob Friesenhahn
On Fri, 5 Feb 2010, Miles Nordin wrote: ls r...@nexenta:/volumes# hdadm write_cache off c3t5 ls c3t5 write_cache disabled You might want to repeat his test with X25-E. If the X25-E is also dropping cache flush commands (it might!), you may be, compared to disabling the ZIL, slowing

Re: [zfs-discuss] Impact of an enterprise class SSD on ZIL performance

2010-02-05 Thread Andrey Kuzmin
On Fri, Feb 5, 2010 at 10:55 PM, Bob Friesenhahn bfrie...@simple.dallas.tx.us wrote: On Fri, 5 Feb 2010, Miles Nordin wrote:   ls r...@nexenta:/volumes# hdadm write_cache off c3t5   ls  c3t5 write_cache disabled You might want to repeat his test with X25-E.  If the X25-E is also dropping

Re: [zfs-discuss] Impact of an enterprise class SSD on ZIL performance

2010-02-05 Thread Ray Van Dolson
On Fri, Feb 05, 2010 at 11:55:12AM -0800, Bob Friesenhahn wrote: On Fri, 5 Feb 2010, Miles Nordin wrote: ls r...@nexenta:/volumes# hdadm write_cache off c3t5 ls c3t5 write_cache disabled You might want to repeat his test with X25-E. If the X25-E is also dropping cache flush

Re: [zfs-discuss] Impact of an enterprise class SSD on ZIL performance

2010-02-05 Thread Miles Nordin
rvd == Ray Van Dolson rvandol...@esri.com writes: ak == Andrey Kuzmin andrey.v.kuz...@gmail.com writes: rvd I missed out on this thread. How would these dropped flushed rvd writes manifest themselves? presumably corrupted databases, lost mail, or strange NFS behavior after the server

[zfs-discuss] Impact of an enterprise class SSD on ZIL performance

2010-02-04 Thread Peter Radig
I was interested in the impact the type of an SSD has on the performance of the ZIL. So I did some benchmarking and just want to share the results. My test case is simply untarring the latest ON source (528 MB, 53k files) on an Linux system that has a ZFS file system mounted via NFS over

Re: [zfs-discuss] Impact of an enterprise class SSD on ZIL performance

2010-02-04 Thread Marc Nicholas
Very interesting stats -- thanks for taking the time and trouble to share them! One thing I found interesting is that the Gen 2 X25-M has higher write IOPS than the X25-E according to Intel's documentation (6,600 IOPS for 4K writes versus 3,300 IOPS for 4K writes on the E). I wonder if it'd

Re: [zfs-discuss] Impact of an enterprise class SSD on ZIL performance

2010-02-04 Thread Andrew Gabriel
Peter Radig wrote: I was interested in the impact the type of an SSD has on the performance of the ZIL. So I did some benchmarking and just want to share the results. My test case is simply untarring the latest ON source (528 MB, 53k files) on an Linux system that has a ZFS file system

Re: [zfs-discuss] Impact of an enterprise class SSD on ZIL performance

2010-02-04 Thread Bob Friesenhahn
On Thu, 4 Feb 2010, Marc Nicholas wrote: Very interesting stats -- thanks for taking the time and trouble to share them! One thing I found interesting is that the Gen 2 X25-M has higher write IOPS than the X25-E according to Intel's documentation (6,600 IOPS for 4K writes versus 3,300 IOPS

Re: [zfs-discuss] Impact of an enterprise class SSD on ZIL performance

2010-02-04 Thread Marc Nicholas
On Thu, Feb 4, 2010 at 10:18 PM, Bob Friesenhahn bfrie...@simple.dallas.tx.us wrote: On Thu, 4 Feb 2010, Marc Nicholas wrote: Very interesting stats -- thanks for taking the time and trouble to share them! One thing I found interesting is that the Gen 2 X25-M has higher write IOPS than

Re: [zfs-discuss] Impact of an enterprise class SSD on ZIL performance

2010-02-04 Thread Bob Friesenhahn
On Thu, 4 Feb 2010, Marc Nicholas wrote: The write IOPS between the X25-M and the X25-E are different since with the X25-M, much more of your data gets completely lost.  Most of us prefer not to lose our data. Would you like to qualify your statement further? Google is your friend. And

Re: [zfs-discuss] Impact of an enterprise class SSD on ZIL performance

2010-02-04 Thread Marc Nicholas
On Thu, Feb 4, 2010 at 10:35 PM, Bob Friesenhahn bfrie...@simple.dallas.tx.us wrote: On Thu, 4 Feb 2010, Marc Nicholas wrote: The write IOPS between the X25-M and the X25-E are different since with the X25-M, much more of your data gets completely lost. Most of us prefer not to lose our