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@xxxxxxxx> 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@xxxxxxxx
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