I don't think this is true.
If you have a SSD disk of 60Gb or 100GB then your TBW/day is really
limited (the disk is small then will wrote always on same sectors).
The bigger is the SSD the longer will be alive, you have limited write
per day then if your disk is bigger you have more sectors to use.
Expecting more than 1year from a SSD as small as 100Gb is really much.
Just think that the same SSD of 1TB then will be 10 years longer with
the same usage.
If what Emmanuel said is real then consumer SSD are the way (10years on
a 1Tb disk).
Then your score it's good (almost amazing) and not bad.
Just switch to bigger SSD and you'll solve all your problems.
Il 02/10/2014 17:14, Ron Allred ha scritto:
One thing being missed,
Samsung 850 Pro has only been available for about 1-2 months.
The OP, noted that drives are failing after approx 1 year. This would
probably mean the SSDs are actually Samsung 840 Pro. The
write-durabilities of 850 and 840 are quite different.
That being said, Samsung 8X0 Pros are desktop drives. Only "Data
Center" grade SSDs should be used with Ceph, with decent TBW/day >= 5
years.
You should be looking at Intel DC37xx, OCZ Intrepid 3800, HGST, etc.
Samsung recently released the 845DC (PRO/EVO) aimed at datacenters.
These have decent TBW specs, but not very much is known about them in
real-use yet.
Spend a full day reading storagesearch.com, it can save you THOUSANDS
of dollars, when selecting an SSD for Datacenter use.
Regards,
Ron
On 09/29/2014 02:31 AM, Emmanuel Lacour wrote:
Dear ceph users,
we are managing ceph clusters since 1 year now. Our setup is typically
made of Supermicro servers with OSD sata drives and journal on SSD.
Those SSD are all failing one after the other after one year :(
We used Samsung 850 pro (120Go) with two setup (small nodes with 2 ssd,
2 HD in 1U):
1) raid 1 :( (bad idea, each SSD support all the OSDs journals writes
:()
2) raid 1 for OS (nearly no writes) and dedicated partition for journals
(one per OSD)
I'm convinced that the second setup is better and we migrate old setup
to this one.
Thought, statistics gives 60GB (option 2) to 100 GB (option 1) writes
per day on SSD on a not
really over loaded cluster. Samsung claims to give 5 years warranty if
under 40GB/day. Those numbers seems very low to me.
What are your experiences on this? What write volumes do you encounter,
on wich SSD models, which setup and what MTBF?
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