Re: [zfs-discuss] Heavy write IO for no apparent reason

2013-01-18 Thread Peter Blajev
Right on Tim. Thanks. I didn't know that. I'm sure it's documented somewhere and I should have read it so double thanks for explaining it. -- Peter Blajev IT Manager, TAAZ Inc. Office: 858-597-0512 x125 On Thu, Jan 17, 2013 at 4:18 PM, Timothy Coalson tsc...@mst.edu wrote: On Thu, Jan 17,

Re: [zfs-discuss] Heavy write IO for no apparent reason

2013-01-18 Thread Freddie Cash
On Thu, Jan 17, 2013 at 4:48 PM, Peter Blajev pbla...@taaz.com wrote: Right on Tim. Thanks. I didn't know that. I'm sure it's documented somewhere and I should have read it so double thanks for explaining it. When in doubt, always check the man page first: man zpool It's listed in the

Re: [zfs-discuss] Heavy write IO for no apparent reason

2013-01-18 Thread Timothy Coalson
On Fri, Jan 18, 2013 at 4:55 PM, Freddie Cash fjwc...@gmail.com wrote: On Thu, Jan 17, 2013 at 4:48 PM, Peter Blajev pbla...@taaz.com wrote: Right on Tim. Thanks. I didn't know that. I'm sure it's documented somewhere and I should have read it so double thanks for explaining it. When in

Re: [zfs-discuss] Heavy write IO for no apparent reason

2013-01-17 Thread Ray Arachelian
On 01/16/2013 10:25 PM, Peter Wood wrote: Today I started migrating file systems from some old Open Solaris servers to these Supermicro boxes and noticed the transfer to one of them was going 10x slower then to the other one (like 10GB/hour). What does dladm show-link show? I'm guessing one

Re: [zfs-discuss] Heavy write IO for no apparent reason

2013-01-17 Thread Peter Wood
I have a script that rotates hourly, daily and monthly snapshots. Each filesystem has about 40 snapshots (zfsList.png - output of 'zfs list | grep -v home/' - the home directories datasets are snipped from the output. 4 users in total.) I noticed that the hourly snapshots on the heaviest

Re: [zfs-discuss] Heavy write IO for no apparent reason

2013-01-17 Thread Bob Friesenhahn
On Thu, 17 Jan 2013, Peter Wood wrote: Unless there is some other way to test what/where these write operations are applied. You can install Brendan Gregg's DTraceToolkit and use it to find out who and what is doing all the writing. 1.2GB in an hour is quite a lot of writing. If this is

Re: [zfs-discuss] Heavy write IO for no apparent reason

2013-01-17 Thread Timothy Coalson
On Thu, Jan 17, 2013 at 5:33 PM, Peter Wood peterwood...@gmail.com wrote: The 'zpool iostat -v' output is uncomfortably static. The values of read/write operations and bandwidth are the same for hours and even days. I'd expect at least some variations between morning and night. The load on

Re: [zfs-discuss] Heavy write IO for no apparent reason

2013-01-17 Thread Jim Klimov
On 2013-01-18 00:42, Bob Friesenhahn wrote: You can install Brendan Gregg's DTraceToolkit and use it to find out who and what is doing all the writing. 1.2GB in an hour is quite a lot of writing. If this is going continuously, then it may be causing more fragmentation in conjunction with your

Re: [zfs-discuss] Heavy write IO for no apparent reason

2013-01-17 Thread Peter Wood
Right on Tim. Thanks. I didn't know that. I'm sure it's documented somewhere and I should have read it so double thanks for explaining it. On Thu, Jan 17, 2013 at 4:18 PM, Timothy Coalson tsc...@mst.edu wrote: On Thu, Jan 17, 2013 at 5:33 PM, Peter Wood peterwood...@gmail.comwrote: The

Re: [zfs-discuss] Heavy write IO for no apparent reason

2013-01-17 Thread Peter Wood
Great points Jim. I have requested more information how the gallery share is being used and any temporary data will be moved out of there. About atime, it is set to on right now and I've considered to turn it off but I wasn't sure if this will effect incremental zfs send/receive. 'zfs send -i

Re: [zfs-discuss] Heavy write IO for no apparent reason

2013-01-17 Thread Bob Friesenhahn
On Thu, 17 Jan 2013, Peter Wood wrote: Great points Jim. I have requested more information how the gallery share is being used and any temporary data will be moved out of there. About atime, it is set to on right now and I've considered to turn it off but I wasn't sure if this will effect

Re: [zfs-discuss] Heavy write IO for no apparent reason

2013-01-17 Thread Bob Friesenhahn
On Thu, 17 Jan 2013, Bob Friesenhahn wrote: For NFS you should disable atime on the NFS client mounts. This advice was wrong. It needs to be done on the server side. Bob -- Bob Friesenhahn bfrie...@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer,

Re: [zfs-discuss] Heavy write IO for no apparent reason

2013-01-16 Thread Bob Friesenhahn
On Wed, 16 Jan 2013, Peter Wood wrote: Running zpool iostat -v (attachment zpool-IOStat.png) shows 1,22K write operations on the drives and 661 on the ZIL. Compare to the other server (who is in way heavier use then this one) these numbers are extremely high. Any idea how to debug any