Hello Daniel,
yes Samsung "Pro" SSD series aren't to much "pro", especially when it's
about write IOPS. I would tend to say get some Intel S4510 if you can
afford it. It you can't you can still try to activate overprovisioning
on the SSD, I would trend to say reserve 10-30% of the SSD for wear
leveling (writing). First check the number of sectors with hdparm -N
/dev/sdX then set a permanent HPA (host protected area) to the disk. The
"p" and no space is important.....
hdparm -Np${SECTORS} --yes-i-know-what-i-am-xxxxx /dev/sdX
Wait a little (!), power cycle and re-check the disk with hdparm -N
/dev/sdX. My Samsung 850 Pro are a little reluctant to accept the
setting, but after some tries or a little waiting the change gets permanent.
At least the Samsung 850 pro stopped to die suddenly with that setting.
Without it the SSD occasionally disconnected from the bus and reappeared
after power cycle. I suspect it ran of of wear something.
HTH,
derjohn
On 13.10.20 08:41, Martin Verges wrote:
> Hello Daniel,
>
> just throw away your crappy Samsung SSD 860 Pro. It won't work in an
> acceptable way.
>
> See
> https://docs.google.com/spreadsheets/d/1E9-eXjzsKboiCCX-0u0r5fAjjufLKayaut_FOPxYZjc/edit?usp=sharing
> for a performance indication of individual disks.
>
> --
> Martin Verges
> Managing director
>
> Mobile: +49 174 9335695
> E-Mail: martin.verges@xxxxxxxx
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>
>
> Am Di., 13. Okt. 2020 um 07:31 Uhr schrieb Daniel Mezentsev <dan@xxxxxxxxxx
>> :
>> Hi Ceph users,
>>
>> Im working on common lisp client utilizing rados library. Got some
>> results, but don't know how to estimate if i am getting correct
>> performance. I'm running test cluster from laptop - 2 OSDs - VM, RAM
>> 4Gb, 4 vCPU each, monitors and mgr are running from the same VM(s). As
>> for storage, i have Samsung SSD 860 Pro, 512G. Disk is splitted into 2
>> logical volumes (LVMs), and that volumes are attached to VMs. I know
>> that i can't expect too much from that layout, just want to know if im
>> getting adequate numbers. Im doing read/write operations on very small
>> objects - up to 1kb. In async write im getting ~7.5-8.0 KIOPS.
>> Synchronouse read - pretty much the same 7.5-8.0 KIOPS. Async read is
>> segfaulting don't know why. Disk itself is capable to deliver well
>> above 50 KIOPS. Difference is magnitude. Any info is more welcome.
>> Daniel Mezentsev, founder
>> (+1) 604 313 8592.
>> Soleks Data Group.
>> Shaping the clouds.
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