Discussion Win10 Pro, Storage Spaces, creation issues resolved, observed read/write performance on striped array of 2.5"/5400 RPM WD Black Drives...

Having a pair of WD Black 5400 RPM laptop drives, 500 GB each, I was curious to play with the often maligned but occasionally praised Storage Spaces, specifically to check it's performance in a simple striped/RAID 0 array within Storage Spaces.

Alas, even the first step on in Creating Pool would error out using one or both drives through multiple attempts, I found a reference in a 4 month old Microsoft posting that disabling the driver within device mngr and rebooting, then re-enabling the driver might clear it. Shockingly...it did!

Upon creating the 'no resiliency'/simple striped array totaling 927 GB, and, attempting a large 14 GByte 7 -Zip folder transfer, I was pleasantly surprised to see very fast speeds the first several GB of data (must be caching it within RAM for the first 6-8 GB?) show transfers ramp from 200 MB/sec up to 800 MB/sec, scale up briefly to 1.4 GB/sec, then see speeds rapidly fall off to the expected ~150 MB/sec transfer speeds... ; CrstalDiskMark also showed ~150 MB sec reads/writes for the sequentials.

As those initial bursts of speeds would of course be impossible for 5400 RPM drives, even a mighty RAID 0, Windows must be just buffering a large chunk to RAM, as, certainly the drives cannot cache that much, I'd think, as the speeds ramped up to 1 - 1.4 GB/sec for the middle third of 2-3 GB of the transfer in the middle before falling off, as predicted.

I'll have to continue testing, see how much things are slowed down with a mirrored RAID-1 (a base single 5400 Rpm drive can only do about 110 MB/sec), etc....

As I'm hearing and now seeing decent reports of Storage Spaces reliability, I'll reconsider using it!

(As a side note, the Storage Space array even shows up as a 927 GB in size, clone/image worthy candidate in Macrium Reflect..)
 

popatim

Titan
Moderator
I did similar a few years ago choosing Raid1. It seemed like every month the raid would lose sync and have to go thru a length resync process which slowed all disk access way down.
I got sick of it this year and broke the array and now use it as two single drives; one updating the backup daily.
 
Deleted the pool, and recreated a new one in a mirrored pair....; oddly enough CrystalDiskMark sequential read and write speeds increased by a few MB/sec afterward, which seems odd...

I will continue to tinker with it, it seems interesting, at least...; might throw in a pair of larger drives, whatever I can get at a reasonable price/capacity point, probably some WD Reds at 6-8 TB.....
 
Added a third drive, created parity array (3 way RAID 0), and, copy speeds for a large file drag (same 14 GB 7-Zip folder) initially 220 MB/sec (caching!), spiked up to 800 MB/sec for a few seconds (caching, NVME), and then quickly plummeted to....<drum roll>....~30 MB/sec writes!

In short, if you want speeds of 140 MB/sec, RAID 1 is fine, as is simple striping of 2 drives (RAID 0 not really quicker anyway, however)...; throw in parity, and, subtract a quick 78% of the performance....
 
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