linux-kernel - Re: [dm-devel] RAID4 with no striping mode request

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAAMCDed2eaygbYxFWDMBKELJ27XKNUZgGsJ1MKQK8qMCUTy+wA@mail.gmail.com>
Date:   Wed, 15 Feb 2023 09:22:33 -0600
From:   Roger Heflin <rogerheflin@...il.com>
To:     Wols Lists <antlists@...ngman.org.uk>
Cc:     Heinz Mauelshagen <heinzm@...hat.com>,
        Kyle Sanderson <kyle.leet@...il.com>,
        linux-raid@...r.kernel.org, Song Liu <song@...nel.org>,
        device-mapper development <dm-devel@...hat.com>,
        John Stoffel <john@...ffel.org>,
        Linux-Kernel <linux-kernel@...r.kernel.org>
Subject: Re: [dm-devel] RAID4 with no striping mode request

The SMART on the disk marks the disk as FAILED when you hit the
manufacturer's posted limit (1000 or 2000 writes average).    I am
sure using a "FAILED" disk would make a lot of people nervous.

The conclusion of you can write as fast as you can and it will take 3
years to wear out would be specific to that specific brand/version
with a given set of chips in it, and may or may not hold to other
vendors/chips/versions, and so may have quite a bit of variation in
it.  I think I remember seeing that, but I don't remember what the
average write rate was.  The one I just found says 200TB of writes on
a 240g drive, so about 8000erases per cell was the lowest failure
rate, with some drives making it 3-5x higher.

On Wed, Feb 15, 2023 at 8:53 AM Wols Lists <antlists@...ngman.org.uk> wrote:
>
> On 15/02/2023 11:44, Roger Heflin wrote:
> > WOL: current SSD's are rated for around 1000-2000 writes.  So a 1Tb
> > disk can sustain 1000-2000TB of total writes.  And writes to
> > filesystem blocks would get re-written more often than data blocks.
> >   How well it would work would depend on how often the data is deleted
> > and re-written.
>
> When did that guy do that study of SSDs? Basically hammered them to
> death 24/7? I think it took about three years of continuous write/erase
> cycles to destroy them.
>
> Given that most drives are obsolete long before they've had three years
> of writes ... the conclusion was that - for the same write load -
> "modern" (as they were several years ago) SSDs would probably outlast
> mechanical drives for the same workload.
>
> (Cheap SD cards, on the other hand ...)
>
> Cheers,
> Wol