>>> ASVINCHANDAR SELVARAJ schrieb am 14.02.2019 um
>>> 06:03
in Nachricht
:
> I tried this
>
> Centos 7.4
>
> echo '4096000' > /sys/block/sdb/queue/max_sectors_kb
>
> But I am getting Input/output error
Actually for FC SAN storage we made the opposite experience: Some filesystems
like ext3 occasionally make bug requests (like 1000 sectors), and such big
requests slow down the SAN storage. We use values significantly below 128kB.
I'd recommend to do analysis before doing tuning, or do an automated tuning
test to find out which values give the best performance in your scenario. You
could also use tools like iftop or iotop to monitor local and remote I/O.
Regards,
Ulrich
>
>
> On Wed, Feb 13, 2019 at 7:29 PM Chan wrote:
>
>> Hello
>>
>> I am having few severe performance issues on my ceph cluster.
>>
>>
>> Scenario 1 )When I mount a rbd volume directly using rbd map command
>> to a linux kernel. I am getting good performance.
>> when I do dd on the above volume, I am getting 380 - 430 MB's. -- I am
>> good with this.
>>
>>
>> Scenario 2 ) I am using iscsi-gateway. iscsi1 and iscs2 as targets and
>> presenting LUNS ro all my initiators.
>>
>>
>> When I do dd on the volumes presented via iscsi gateway, my performance is
>> 10 to 25 MB's. which is very poor.
>>
>> I am gwcli commandline and connot use the belwo command
>>
>> "create images image=test1 size=100g max_data_area_mb=128"
>>
>> ' Unexpected keyword error '
>>
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>
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