Hi Kees,
Assuming 3 replicas and collocated journal each RBD write will trigger 6 SSD writes (excluding FS overhead and occasional re-balance).
Intel has 4 tiers of Data center SATA SSD (other manufacturers may have fewer):
- S31xx: ~0.1 DWPD (counted on 3 years): Very read intensive
- S35xx: ~1 DWPD: Read intensive
- S36xx: ~3 DWPD: Mixed workloads
- S37xx: ~10 DWPD: Write intensive
(DWPD = Disk write per day)
For example a cluster of 90* 960GB S3520 has an write endurance of 26.25 PB, so around 14 TB/day.
IMO the S3610 (maybe soon the S3620 :D) is a good enough middle of the road option if you don’t know the write volume of the RBD backed VMs. Then after a few months in production you can use the SMART data and re-evaluate.
I cannot highlight enough how important it is to monitor the SSD wear level.
Cheers,
Maxime
On 16/01/17 11:36, "ceph-users on behalf of Kees Meijs" <ceph-users-bounces@xxxxxxxxxxxxxx on behalf of kees@xxxxxxxx> wrote:
Hi Maxime,
Given your remark below, what kind of SATA SSD do you recommend for OSD
usage?
Thanks!
Regards,
Kees
On 15-01-17 21:33, Maxime Guyot wrote:
> I don’t have firsthand experience with the S3520, as Christian pointed out their endurance doesn’t make them suitable for OSDs in most cases. I can only advise you to keep a close eye on the SMART status of the SSDs.
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