Just 300 GiB, actually. But that's still rather large and could skew things
depending on OST size.
- Patrick
On 9/21/18, 4:43 PM, "lustre-discuss on behalf of Andreas Dilger"
<lustre-discuss-boun...@lists.lustre.org on behalf of adil...@whamcloud.com>
wrote:
On Sep 21, 2018, at 00:43, fırat yılmaz <firatyilm...@gmail.com> wrote:
>
> Hi Andreas,
> Tests are made with dd, The test folder is created by the related
application company, i will check that when i have connection. OST's has
%85-86 free space and filesystem mounted with flock option, i will ask for it
to remove and test again.
The "flock" option shouldn't make any difference, unless the application is
actually doing userspace file locking in the code. Definitely "dd" will not be
using it.
What does "lfs getstripe" on the first and second file as well as the
parent directory show, and "lfs df" for the filesystem?
> Read test dd if=/vol1/test_read/dd.test.`hostname` of=/dev/null bs=1M
count=300000
>
> Write test dd if=/dev/zero of=/vol1/test_read/dd.test.2.`hostname` bs=1M
count=300000
This is creating a single file of 300TB in size, so that is definitely
going to skew the space allocation.
Cheers, Andreas
>
> On Thu, Sep 20, 2018 at 10:57 PM Andreas Dilger <adil...@whamcloud.com>
wrote:
> On Sep 20, 2018, at 03:07, fırat yılmaz <firatyilm...@gmail.com> wrote:
> >
> > Hi all,
> >
> > OS=Redhat 7.4
> > Lustre Version: Intel® Manager for Lustre* software 4.0.3.0
> > İnterconnect: Mellanox OFED, ConnectX-5
> > 72 OST over 6 OSS with HA
> > 1mdt and 1 mgt on 2 MDS with HA
> >
> > Lustre servers fine tuning parameters:
> > lctl set_param timeout=600
> > lctl set_param ldlm_timeout=200
> > lctl set_param at_min=250
> > lctl set_param at_max=600
> > lctl set_param obdfilter.*.read_cache_enable=1
> > lctl set_param obdfilter.*.writethrough_cache_enable=1
> > lctl set_param obdfilter.lfs3test-OST*.brw_size=16
> >
> > Lustre clients fine tuning parameters:
> > lctl set_param osc.*.checksums=0
> > lctl set_param timeout=600
> > lctl set_param at_min=250
> > lctl set_param at_max=600
> > lctl set_param ldlm.namespaces.*.lru_size=2000
> > lctl set_param osc.*OST*.max_rpcs_in_flight=256
> > lctl set_param osc.*OST*.max_dirty_mb=1024
> > lctl set_param osc.*.max_pages_per_rpc=1024
> > lctl set_param llite.*.max_read_ahead_mb=1024
> > lctl set_param llite.*.max_read_ahead_per_file_mb=1024
> >
> > Mountpoint stripe count:72 stripesize:1M
> >
> > I have a 2Pb lustre filesystem, In the benchmark tests i get the
optimum values for read and write, but when i start a concurrent I/O operation,
second job throughput stays around 100-200Mb/s. I have tried lovering the
stripe count to 36 but since the concurrent operations will not occur in a way
that keeps OST volume inbalance, i think that its not a good way to move on,
secondly i saw some discussion about turning off flock which ended up
unpromising.
> >
> > As i check the stripe behaviour,
> > first operation starts to use first 36 OST
> > when a second job starts during a first job, it uses second 36 OST
> >
> > But when second job starts after 1st job it uses first 36 OST's which
causes OST unbalance.
> >
> > Is there a round robin setup that each 36 OST pair used in a round
robin way?
> >
> > And any kind of suggestions are appreciated.
>
> Can you please describe what command you are using for testing. Lustre
is already using round-robin OST allocation by default, so the second job
should use the next set of 36 OSTs, unless the file layout has been specified
e.g. to start on OST0000 or the space usage of the OSTs is very imbalanced
(more than 17% of the remaining free space).
>
> Cheers, Andreas
> ---
> Andreas Dilger
> Principal Lustre Architect
> Whamcloud
>
>
>
>
>
>
>
Cheers, Andreas
---
Andreas Dilger
Principal Lustre Architect
Whamcloud
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