Please send us the diagnostics (HTML UI -> System Page -> Run
Diagnostics) to supp...@quadstor.com

Also please run btrace against the following devices when running the fio device
btrace -w 120 /dev/quadstor/<vdisk name> > /tmp/vdisk.out 2>&1 &
btrace -w 120 <ssd cache device> > /tmp/cache.out 2>&1 &
btrace -w 120 /dev/<ssd device> > /tmp/ssd.out 2>&1 &
btrace -w 120 /dev/<md device> > /tmp/md.out 2>&1 &

The btrace command will terminate after two minutes.

Please note that the data written to the SSD cache need not be sent to
the md device yet. It will be done so only when the cache is filling
up. If that is what you are seeing, then there is no issue here.

On Tue, Sep 20, 2016 at 5:06 AM, Zac Durham <zacdur...@gmail.com> wrote:
> I'm running randread and randwrites with fio. I would expect something out
> of the cache device- instead nothing.....
>
> I've considered using bcache, but I would have to build that for centos 7.
> Not out of the question, just not in my immediate wheelhouse.
>
> Thanks for the response, very much.
>
> Zac
>
> On Monday, September 19, 2016 at 4:41:45 PM UTC-4, quadstor wrote:
>>
>> You could try btrace on the device to see the IO activity.
>>
>> If you are running tests with zeroed data, then they will be
>> deduplicated. So there will be negiligible data written to the SSD
>> disk by the vdisk.
>>
>> On Mon, Sep 19, 2016 at 4:33 AM, Zac Durham <zacd...@gmail.com> wrote:
>> > There's a few topics out there on this subject but I can't get my head
>> > around any of them....
>> >
>> > I have 3 x 2TB in software (mdadm) RAID5 (yeah, yeah I know) and a spare
>> > 120G SSD to use as cache. Currently I use flashcache to back the entire
>> > md
>> > device but do not realize any benefit in doing so (nor do I see any
>> > activity
>> > on the cache device when performing I/O against the array).
>> >
>> > Where is my approach flawed? I've also tried fronting the qs vdisks
>> > themselves with the SSD device to no avail either.
>> >
>> > Any help would be appreciated.
>> >
>> > -Z
>> >
>> >
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