Seagate FireCuda not recommended for RAID?

[cbn]

I found the following post from Jul 2016 with a report about Seagate recommending against RAID for FireCuda:

http://www.tomshardware.com/answers/id-3139762/seagate-firecuda-drives-raid.html

And here back in July 2017:

https://www.reddit.com/r/pcmasterrace/comments/6j1vrk/seagate_firecudaraid_questions/

(With this noted I was not able to find any specific mention of RAID in the FireCUDA product manual--> http://www.seagate.com/support/internal-hard-drives/desktop-hard-drives/firecuda-3-5/ )

I also noticed Seagate still has NAND in their enterprise SAS Hard drives announced Oct. 2016 (which I know would be used in RAID):

https://www.anandtech.com/show/1072...rprise-performance-15k-hdds-with-nand-caching

The new Seagate Enterprise Performance 15K v6 HDDs come in 300, 600 and 900 GB configurations. Just like their predecessors, they use a dual port SAS 12 Gbps interface as well as a 2.5”/15 mm form-factor. The new Enterprise Performance 15K v6 hard drives have single or dual level caches: either a 256 MB of DRAM cache only or a 256 MB of DRAM cache and a 16 GB of NAND flash cache (4Kn/512E models only). The latter is used for caching of frequently used “hot” data to maximize read performance and reduce latencies (Seagate offers similar capability with its consumer-grade FireCuda and other SSHDs). It is noteworthy that Seagate reduced the amount of NAND flash compared to previous-generation 15K HDDs, but the company seems to believe that its improved caching algorithms will ensure that the new drives are faster than their predecessors.

When compared to predecessors, the new sixth-generation 15K HDDs are rated for a 27% increase in sequential read write speed: up to 315 MB/s. In addition, the drives also promise 100% faster random write performance. Seagate claims that its advanced caching algorithms promote hot data three times faster when compared to 512N drives without NAND, but it does not reveal exact performance numbers for its NAND cache.

???

 

[cbn]

https://forums.anandtech.com/threads/intel-rst-and-raid-1.2518689/#post-39076684

The Firmware in FireCuda drives causes a large amount of variance in write committals to the drive (because the amount dedicated to writes and reads varies). Because of the variance, the RAID 1 array becomes the lowest common denominator of any one drive trying to commit writes. The firmware in the FireCuda drives is not designed to work with a predictable variance to other drives in RAID, so performance is perpetually poor on them unless you disable the buffer flushing.

Seagate makes drives that can handle RAID and have a NAND cache (referred to as TurboBoost), but they are of course far more expensive than what you paid for the FireCuda drives. The FireCuda drives you got won't work in the way you want them to.

 

[cbn]

Firecuda with UnRAID, SnapRAID and FlexRAID?

 

[wirelessenabled]

One of my clients has a fairly small, 500 MB Firebird database. The database server runs with Raid 1, ie mirroring. It was time to swap out the drives so I put in a pair of Seagate 1 TB SSHD drives.

What a mistake! The database slowed to a crawl serving out to the clients with hesitations in the 10+ second range.

I changed out to a pair of Western Digital 7200 rpm drives and performance came back. Who would have thunk?

 

[dave_the_nerd]

Firecuda with UnRAID, SnapRAID and FlexRAID?

UnRAID would probably work okay, since it's primarily reading/writing to one drive at a time, and each drive has a distinct file system.

Final write acknowledgement would presumably be slower, since the system would be waiting for parity calculation and confirmation from the parity drive (which may or may not have a NAND cache.)

It'd be worth a test though.