TS-653D SSD Cache - Can just one be installed?
Are you able to use just one SSD for cache? If so, is it asking for trouble to add a consumer SATA SSD? I'm unsure of what the daily writes would be perhaps someone who has done this would have an idea.
thanks
Posted Oct 18, 2020, 12:13 AM UTC
34
AFAIK you can use 1 SSD as read cache, but you need two in RAID 1 when using it as write cache. You can use consumer SSDs, but I personally recommend Samsung Pro.
I personally found the gain in throughput underwhelming, even with 10 GBit/s speed...
Wait? You need (as in forced) to have 2 for in Raid 1/0 to use it as a write cache? Or that is what you are recommending?
RAID 1 not 0. The NAS is doing that automagically.
I hope I don't mix it up with Synology...
Given how tiering functions in a SAN and assuming it works the same in these NAS devices, it's understandable. The system won't commit the writes to the drives until the spinning disks have time to accept the transaction. Typically this isn't a long period of time in human terms but long enough in data terms that you could lose data on multiple volumes due to a failure of a cache device. Or perhaps they have another reason but I'd hazard this is the cause. CYA as well.
Come to think of it even with extremely short delays in commits all it takes is one bad cell on that ssd and you have big problems.