Linux RAID subsystem development
 help / color / mirror / Atom feed
From: pg@lxra2.for.sabi.co.UK (Peter Grandi)
To: Linux RAID <linux-raid@vger.kernel.org>
Subject: Re: RAID5 Performance
Date: Thu, 28 Jul 2016 18:45:46 +0100	[thread overview]
Message-ID: <22426.17610.799702.846715@tree.ty.sabi.co.uk> (raw)
In-Reply-To: <0eee845d-b833-0a92-8fe6-a2522218a0e6@websitemanagers.com.au>

[ ... ]
> My concern is that even if I solve *this* bottleneck (ie, the
> 530 model SSD being too busy), that there will be another
> bottleneck afterwards

There is always another bottleneck ;-).

[ ... ]
> I'm not sure, but I think I've had one of the 480GB drives
> fail, and 3 of the smaller 60GB and 80GB drives fail. So far,
> only the 480G failure was "catastrophic", the others were
> still operating . All were replaced by Intel.
[ ... ]

When flash SSD drives run over their "expected" write amount
they behave differently:

  http://www.sabi.co.uk/blog/15-one.html#150406b

Intel flash SSDs apparently do the following:

* They switch immediately to read-only.
* On the next power up they refuse even to *read*.

BTW, as to the Samsung SM863 there is a relatively recent "group
test" here:

  http://www.storagereview.com/samsung_sm863_ssd_review

The average and max latency graphs are interesting, especially
those under "Preconditioning Curve".

  reply	other threads:[~2016-07-28 17:45 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-07-27  2:24 RAID5 Performance Adam Goryachev
2016-07-27  3:15 ` Brad Campbell
2016-07-27  5:36 ` Doug Dumitru
2016-07-27 23:26   ` Adam Goryachev
     [not found]   ` <7af0cc98-e395-9446-05eb-a6c0ca20f187@websitemanagers.com.au>
2016-07-28  0:11     ` Doug Dumitru
2016-07-28 13:08       ` Anthony Youngman
2016-07-28 14:10       ` Adam Goryachev
2016-07-28 17:45         ` Peter Grandi [this message]
2016-07-27 14:26 ` Peter Grandi
2016-07-27 17:38   ` Doug Dumitru
2016-07-28 12:19     ` Peter Grandi
2016-07-28 13:28       ` Peter Grandi
2016-07-28 13:57         ` Adam Goryachev
2016-07-28 17:20           ` Peter Grandi
2016-07-28 18:45             ` Doug Dumitru
2016-08-02  7:09             ` Adam Goryachev
2016-08-03 21:23               ` Peter Grandi
2016-07-28 13:50       ` Adam Goryachev

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=22426.17610.799702.846715@tree.ty.sabi.co.uk \
    --to=pg@lxra2.for.sabi.co.uk \
    --cc=linux-raid@vger.kernel.org \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox