[stgt] Large number of abort_task_set followed by conn_close

[Brian Schaefer]

> Why not simply use a file for tgtd?
Simply put: I didn't know I could. My distro didn't include the
manpage for targets.conf, and it's not on your webpage. I see in the
HOW-TOs that this is possible with tgtadm, but I wasn't ready to take
that leap. I downloaded the latest release from github and did a MAKE
on the doc directory, which clued me in to this bit:

       backing-store <path>
           Defines a logical unit (LUN) exported by the target. This
may specify either a regular file, or a block device.

So then, instead of "backing-store /dev/loop0", i should be able to
use the file directly, e.g. "backingstore /data/sata200/vmds200.loop"?

I'll give that a shot after i backup the datastore. That should buy me
some time until i can get some physical drives for this purpose.

--Brian

On Mon, Jun 25, 2012 at 10:29 PM, FUJITA Tomonori
<fujita.tomonori at lab.ntt.co.jp> wrote:
> On Mon, 25 Jun 2012 10:43:36 -0500
> Brian Schaefer <brian.schaefer at gmail.com> wrote:
>
>> Team,
>>
>> I'm trying to stabilize my homebrew iSCSI server that I'm using as a
>> ESX datastore. Under heavy usage, i see the following behavior:
>>
>> Jun 25 10:00:17 fileserver tgtd: abort_task_set(1150) found 177db9 0
>> [message repeats ~100 times, increasing the found hex address]
>> Jun 25 10:00:20 fileserver tgtd: conn_close(101) connection closed, 0x8cdbe8 70
>> Jun 25 10:00:20 fileserver tgtd: conn_close(107) sesson 0x8cdee0 1
>> Jun 25 10:00:20 fileserver tgtd: conn_close(101) connection closed, 0x8cc1f8 5
>> Jun 25 10:00:20 fileserver tgtd: conn_close(107) sesson 0x8cd400 1
>
> Sounds like the performance of your device is not enough.
>
>
>> I think this may be due to the fact that i'm using a /dev/loop0
>> devices as the backing store:
>
> Maybe. Loopback devices degrades the performance.
>
>> default-driver iscsi
>> <target iqn.2012-04.com.example:vmds200>
>>         backing-store /dev/loop0
>>         initiator-address 192.168.3.2
>>         initiator-address 192.168.3.6
>> </target>
>>
>> In case it's relevant, /dev/loop0 gets created at boot (manually,
>> since this was supposed to be temporary anyway). It's a file i created
>> with DD, located on an MDADM RAID1 of 2x 2TB disks (2TB total
>> storage). The file itself if 500GB.
>
> Why not simply use a file for tgtd?
>
>
>> I'm running CentOS6 with kernel 2.6.32-220.17.1.el6.x86_64, and
>> scsi-target-utils-1.0.14-4.el6.x86_64.
>>
>> In order to stabilize the system, would it be better to
>>
>> a) migrate to the OSD storage type
>> b) migrate to real physical disks (probably another MDADM RAID1)
>> c) The loop device isn't the issue, I have something else messed up.
>> --
>>
>>
>> --Brian
>> --
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-- 


--Brian
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