Chris Worley, on 09/15/2009 09:01 PM wrote:
On Tue, Sep 15, 2009 at 10:57 AM, Vladislav Bolkhovitin <v...@vlnb.net> wrote:
Chris Worley, on 09/15/2009 08:53 PM wrote:
On Tue, Sep 15, 2009 at 10:43 AM, Vladislav Bolkhovitin <v...@vlnb.net>
wrote:
Chris Worley, on 09/15/2009 07:50 PM wrote:
On Tue, Sep 15, 2009 at 12:10 AM, Bart Van Assche
<bart.vanass...@gmail.com> wrote:
On Tue, Sep 15, 2009 at 1:03 AM, Chris Worley <worl...@gmail.com>
wrote:
On Mon, Sep 14, 2009 at 12:51 PM, Vladislav Bolkhovitin <v...@vlnb.net>
wrote:
Chris Worley, on 09/11/2009 11:50 PM wrote:
I've definitely removed the switch/firmware from being the cause.
I'm thinking the reason you can't repeat the test may be latency
related. We get ~50usecs average latency (on small block sizes),
which can't be achieved using regular SSD's (and rotating drives are
nowhere close). Maybe a ramdisk would help repeat the issue.
I think you should try to reproduce the problem with ramdisk or
nullio.
By
so you will eliminate possible influence of the SSD backend.
W/ 12GB RAM in the target, I created a 7GB ramdisk:
mount -t ramfs -o size=7g ramfs /mnt/
dd if=/dev/zero of=/mnt/foo bs=1024k count=7000
echo "open ramdisk /mnt/foo" > /proc/scsi_tgt/vdisk/vdisk
echo "add ramdisk 2" >/proc/scsi_tgt/groups/Default/devices
Then, on the initiator, I tested it... and it hung during sequential
8KB block reads:
fio --rw=read --bs=8k --numjobs=64 --iodepth=64 --sync=0 --direct=1
--randrepeat=0 \
--group_reporting --ioengine=libaio --filename=/dev/sde --name=test
--loops=10000 --runtime=600
Note that I was running the SM on the target this time too.
Which Linux distro was installed on the inititiator and on the target
? And if applicable, which OFED version ? Which kernel messages were
logged by SRPT around the time the issue occurred (after having
enabled SRPT logging first) ?
As logging hadn't helped this issue previously, I've not been enabling
it. That plus the kernel hacks needed to invoke logging, it's not
worth enabling.
This was with Ubuntu 8.10, built-in IB on the 2.6.27-14-server kernel.
I couldn't get ramdisks working w/ SCST in RHEL5.2. When running:
echo "open ramdisk /mnt/foo" > /proc/scsi_tgt/vdisk/vdisk
I get the error:
dev_vdisk: ***ERROR***: Wrong f_op or FS doesn't have required
capabilities
... which doesn't occur in the Ubuntu kernel, so I've been unable to
test RHEL kernels w/ ramdisks. In general, this problem occurs w/ 8KB
and smaller blocks w/ the Ubuntu kernels, and 2KB and smaller blocks
w/ RHEL kernels.
Use ramfs instead.
Do you mean:
mount -t ramfs -o size=7g ramfs /mnt/
You should then create a file on it and use it.
That's what I'm doing, I believe. From above:
mount -t ramfs -o size=7g ramfs /mnt/
dd if=/dev/zero of=/mnt/foo bs=1024k count=7000
echo "open ramdisk /mnt/foo" > /proc/scsi_tgt/vdisk/vdisk
echo "add ramdisk 2" >/proc/scsi_tgt/groups/Default/devices
... but the "open", on RHEL5.2 kernel 2.6.18-92.el5, generates the
following kernel messages:
dev_vdisk: Registering virtual FILEIO device ramdisk
scst: Processing thread started, PID 9629
scst: Processing thread started, PID 9630
scst: Processing thread started, PID 9631
scst: Processing thread started, PID 9632
scst: Processing thread started, PID 9633
dev_vdisk: ***ERROR***: Wrong f_op or FS doesn't have required capabilities
scst: ***ERROR***: New device handler's vdisk attach() failed: -22
scst: Processing thread PID 9629 finished
scst: Processing thread PID 9630 finished
scst: Processing thread PID 9631 finished
scst: Processing thread PID 9632 finished
scst: Processing thread PID 9633 finished
scst: Failed to attach to virtual device ramdisk
Chris
?
That's what I'm doing.
That's strange. I'm doing it all the time, although with not so old
kernels as 2.6.18.
Chris
Chris
Bart.
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