[stgt] tgtd memory usage

[Stepan Fedorov]

So... my first question is still actual.

We plan to study source code, but before, maybe. somebody who already know it can tell me - how we can reduce tgtd memory usage?

Thank you!

25.03.2011, в 0:10, Stepan Fedorov написал(а):

> 
> OK! I do some tests on my test environment and here is the results:
> 
> My target node has 12Gb of memory. I created 300 LUN's on it - tgtd process virtual size become something above 13Gb.
> 
> Next, i attach this LUNs on three initiator nodes - 100 LUNs per node.
> 
> Now - my task is to initiate some IO on all of this LUNs in parallel, to see - what happen with tgtd.
> 
> To do this, i created LVM striped volume (/dev/vbd0/megadisk0) from 100 iSER-attached LUNs on each initiator node.
> 
> Next, i run e2fsck /dev/vbd0/megadisk0 on three nodes. During this process, i got messages about IO errors on all LUNs in dmesg on all three nodes, because tgtd segfaults on target node, with this message in dmesg:
> [734121.705847] tgtd[18959]: segfault at 0 ip (null) sp 00007fff04d22118 error 14 in tgtd[400000+4a000]
> 
> 
> 24.03.2011, в 14:06, FUJITA Tomonori написал(а):
> 
>> On Thu, 24 Mar 2011 14:09:14 +0300
>> Степан Фёдоров <stepan.fedorov at clodo.ru> wrote:
>> 
>>> Hm... i create 666 targets with one LUN per target on node with 12Gb
>>> of memory, and in top i see this:
>>> 
>>> PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
>>> 
>>>                                                                7862
>>> root       20   0 22.4g  1.6g 1144 S    2 13.4   7:39.18
>>> /usr/sbin/tgtd
>>> 
>>> VIRT, and RES values grows while i attach this targets on initiator
>>> node. What will happen, if tgt begin usage of all this memory while
>>> serving it's targets? It will be killed by oom killer?
>> 
>> tgtd can avoid oom killer by setting /proc/{pid}/oom_adj.
>> 
>> 
>>> Ooops. While i write this - on initiator side i got in dmesg a "BUG" message )
>> 
>> Needs to report it to open-iscsi mailing list.
> 
> Stepan Fedorov
> sf at clodo.ru
> 
> 
> 

Stepan Fedorov
sf at clodo.ru



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