Recommendation for used SAS SSDs

[llowrey]

I would like to build an aprox. 16TB raid0 array of SSDs. My backplane has plenty of dual port SAS3 12Gb/s capacity but I lack PCIe lanes for enough m.2 or u.2 NVMe devices.

Usage is ~90/10 reads/writes and almost entirely small random iops (lots of 4k). DWPD would be around 10%. The data is actually a mirror of data that is regularly backed up so raid0 seems reasonable in the case. If a drive blows up and I'm off-line for a few days while I wait for a replacement, that's ok.

I would prefer dual port since I might end up with sequential workloads in the future.

A single 16TB device would probably be ok but I would prefer multiple devices, up to 8, just to spread out my failure risk (replacement cost). I would like to keep the cost below $2K. There seem to be quite a few capacity options in that range, a lot of drives on eBay do tend to be quite old (2016-ish), and it's not fun trying to figure out if a drive is single or dual port.

Any advice or recommendations would be greatly appreciated!

 

[Whaaat]

a lot of drives on eBay do tend to be quite old (2016-ish), and it's not fun trying to figure out if a drive is single or dual port.

no need to gamble, sas ssds made in 2016 are 100% dual port.

 

[llowrey]

Interesting. So, after some investigation I came to understand that I had assumed that devices had low sequential rates due to being single port but in fact they were slow... because they were slow.

So, I am now considering:

8x 1.92TB Samsung PM1633(a) - slow but cheapest
4x 3.84TB Samsung PM1643(a) - fast but a bit over budget
4x 3.84TB HGST SS530 - fast but a bit over budget

I haven't come across very many other options. I have seen Toshiba KPM51RUG3T84 and HGST SSD1600MR but not many of them.

Any other models I should be considering?

I'm leaning toward PM1633 but am a little concerned about age (all made in 2016). My workload is low duty cycle so I don't think I'll need to worry about wear or lifetime use.

 

[bilbo1337]

You could get 5 of these to get 16TB: HGST Dell Ultrastar SS300 3.2TB 3D MLC SAS 12Gb/s 2.5" Enterprise SSD (HUSMR3232ASS204) - Newegg.com

It's over your budget of $2K but SAS SSDs are expensive..

 

[EffrafaxOfWug]

I would like to build an aprox. 16TB raid0 array of SSDs.
...
A single 16TB device would probably be ok but I would prefer multiple devices, up to 8, just to spread out my failure risk (replacement cost).

I'm sure you're aware, but just to be patently clear - with a RAID0 of two drives you're doubling your failure risk, not reducing it, as with RAID0 you lose all your data if any one of the drives in the array fails. Three drives you're tripling your failure risk, four drives you're quadrupling it, etc...

 

[llowrey]

I'm sure you're aware, but just to be patently clear - with a RAID0 of two drives you're doubling your failure risk, not reducing it, as with RAID0 you lose all your data if any one of the drives in the array fails. Three drives you're tripling your failure risk, four drives you're quadrupling it, etc...

Indeed. I suppose I should have said "failure cost" and not "failure risk". In my case the downtime cost is relatively low, backups are frequent and tested and restores are quick. I would rather replace a $200 drive (or two) than a $1,600 drive.