[lustre-discuss] How to find the performance degrade reason

Andreas Dilger adilger at whamcloud.com
Sun Sep 16 21:01:57 PDT 2018

The "lfs getstripe /path/to/file" command will tell you which OSTs are used for each file.  Different files will be allocated from different OSTs.  By default, stipe_count = 1, so each file will be on a single OST.

On Sep 16, 2018, at 03:05, Zeeshan Ali Shah <javaclinic at gmail.com> wrote:
> Is it possible to know which OST are actively in used for a  client lets say during rsync copy .
> On Thu, Sep 13, 2018 at 2:17 AM Cameron Harr <harr1 at llnl.gov> wrote:
>> I realize I didn't answer all the questions, so:
>> 1) For a file-system-level view, we use ltop, a handy utility that's in the LMT package (https://github.com/LLNL/lmt). If you want to pinpoint OST or MDT tests, you could lock a file/dir to a particular OST/MDT and then use 'zpool iostat ...' to monitor I/O for that device
>> 2) Again, I'd recommend getting ltop. 'zpool iostat' can give you numerous performance statistics as well.
>> On 09/12/2018 04:11 PM, Cameron Harr wrote:
>>> Use 'zpool iostat -v ...'. You can review the man page for lots of options, including latency statistics.
>>> Cameron
>>> On 09/10/2018 11:21 AM, Zeeshan Ali Shah wrote:
>>>> Dear All,
>>>> Suddenly our lustre installation become dead slow, copying data from local source to lustre result around 20MB/sec before it was above 600 MB.
>>>> i checked zfs status -xv and (all pool healths are ok)
>>>> 1) How to check which OSTs are involved during data write operation ?
>>>> 2) How to check Meta data (read and write) stats ?
>>>> 3) any other advice to drill down the reason ..
>>>> /Zeeshan

Cheers, Andreas
Andreas Dilger
Principal Lustre Architect

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