Nice!
Pleased that the general idea worked well for you!
I'm also relieved that you did not follow my recommendation exactly -
I'm been trialling a Samsung 960 Evo (256GB) and Intel 600p (256GB) and
I've stumbled across the serious disadvantages of (consumer) M.2 drives
using TLC NAND - terrible sustained write performance! While these guys
can happily do ~ 2GB/s reads, their write performance is only 'burst
capable'. They have small SLC NAND 'write caches' that do ~1GB/s for a
*limited time* (10-20s) and after that you get ~ 200 MB/s! Ouch - my old
Crucial 550 can do 350 MB/s sustained writes (so two of them in RAID0
are doing 700 MB/s for hours).
Bigger capacity drives can do better - but overall I'm not that
impressed with the current trend of using TLC NAND.
regards
Mark
On 21/07/17 00:50, Charles Nadeau wrote:
Mark,
I received yesterday a second server having 16 drives bays. Just for a
quick trial, I used 2 old 60GB SSD (a Kingston V300 and a ADATA SP900)
to build a RAID0. To my surprise, my very pecky RAID controller (HP
P410i) recognised them without a fuss (although as SATAII drives at
3Gb/s. A quick fio benchmark gives me 22000 random 4k read IOPS, more
than my 5 146GB 10k SAS disks in RAID0). I moved my most frequently
used index to this array and will try to do some benchmarks.
Knowing that SSDs based on SandForce-2281 controller are recognised by
my server, I may buy a pair of bigger/newer ones to put my tables on.
Thanks!
Charles
On Sat, Jul 15, 2017 at 1:57 AM, Mark Kirkwood
<mark.kirkwood@xxxxxxxxxxxxxxx <mailto:mark.kirkwood@xxxxxxxxxxxxxxx>>
wrote:
Thinking about this a bit more - if somewhat more blazing
performance is needed, then this could be achieved via losing the
RAID card and spinning disks altogether and buying 1 of the NVME
or SATA solid state products: e.g
- Samsung 960 Pro or Evo 2 TB (approx 1 or 2 GB/s seq scan speeds
and 200K IOPS)
- Intel S3610 or similar 1.2 TB (500 MB/s seq scan and 30K IOPS)
The Samsung needs an M.2 port on the mobo (but most should have
'em - and if not PCIe X4 adapter cards are quite cheap). The Intel
is a bit more expensive compared to the Samsung, and is slower but
has a longer lifetime. However for your workload the Sammy is
probably fine.
regards
Mark
On 15/07/17 11:09, Mark Kirkwood wrote:
Ah yes - that seems more sensible (but still slower than I
would expect for 5 disks RAID 0).
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