Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD

From	Michael Stone <mstone@debian.org>
Newsgroups	linux.debian.user
Subject	Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD
Date	2022-01-03 19:30 +0100
Message-ID	<DBAfL-3gz-1@gated-at.bofh.it> (permalink)
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On Mon, Jan 03, 2022 at 10:33:59AM -0500, Dan Ritter wrote:
>Michael Stone wrote:
>> On Mon, Jan 03, 2022 at 08:42:29AM -0300, Jorge P. de Morais Neto wrote:
>> > Indeed I use such high compression to prolong SSD lifetime.
>>
>> This is probably misguided and useless at best, at worst you're causing
>> additional writes because compressed data is generally hard to modify in
>> place without rewriting substantial portions. Concerns about SSD life are
>> generally overblown unless you've got really unusual usage patterns (in
>> which case compressing things is unlikely to make a difference).
>
>SSDs don't modify in place. The compression is probably good for
>overall bandwidth of I/O, depending on CPU utilization.

I'm aware of how SSDs work. The question is how much rewriting is 
triggered by altering a byte in a compressed file, and how that 
interacts with the SSD's erase blocks and SLC cache. In most cases the 
effects are probably negligable (at least as much as any possible 
improvement from using compression) but in pathological cases it might 
increase rather than decrease write amplification. 

Anyway, there may be reasons to want to use compression on a given 
device, but SSD longevity shouldn't be one of them.

In my experience it doesn't do much for performance because in places 
*where it matters* compression is usually being done at a higher level 
anyway, and much more efficiently. That said, it can help sometimes but 
it's going to be extremely application-dependent.

>> For reference, my main desktop which tracks debian unstable and gets pretty
>> much constant updates, does package builds, etc., has after several years
>> used...2% of its primary SSDs write capacity. Most modern SSDs will never be
>> used anywhere close to their limits before being discarded as functionally
>> obsolete. Just don't worry about it and focus on other things.
>
>This is largely true on desktops and laptops, not so true on
>servers.

And, of course, we're talking about a laptop.

If we were talking about servers it wouldn't generally be a runtime 
concern on a modern system if write volume is accounted for when 
provisioning--there are extremely long-lived SSDs, they just cost more. 
If you put commodity laptop HDs in a server and write literally hundreds 
of TBs per day to them they also tend to fail faster than higher grade 
HDs (just without the counter telling you when they'll stop) so that's 
not a novel concern to account for when designing a system. If you're 
running servers you should probably monitor SSD health, but that's not 
different in practical terms than monitoring SMART predictive failures 
for HDs and dealing with them as necessary. In reality, even with all 
the hand-wringing about SSD write limits, modern parts are much more 
reliable than HDs. Most of the bad experiences with SSDs that get so 
much attention (excepting bad batches, which can happen with anything) 
relate to devices many generations obsolete.

Thread

Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD "Jorge P. de Morais Neto" <jorge+list@disroot.org> - 2021-12-08 15:30 +0100
  Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD piorunz <piorunz@gmx.com> - 2021-12-08 16:00 +0100
    Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Jorge P. de Morais Neto <jorge+list@disroot.org> - 2021-12-08 20:40 +0100
      Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD piorunz <piorunz@gmx.com> - 2021-12-09 00:00 +0100
        Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Jorge P. de Morais Neto <jorge+list@disroot.org> - 2022-01-02 17:40 +0100
          Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD piorunz <piorunz@gmx.com> - 2022-01-03 00:40 +0100
            Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Jorge P. de Morais Neto <jorge+list@disroot.org> - 2022-01-03 12:50 +0100
              Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Michael Stone <mstone@debian.org> - 2022-01-03 16:20 +0100
                Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Dan Ritter <dsr@randomstring.org> - 2022-01-03 17:00 +0100
                Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Michael Stone <mstone@debian.org> - 2022-01-03 19:30 +0100
                Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Jorge P. de Morais Neto <jorge+list@disroot.org> - 2022-01-04 01:00 +0100
                Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Michael Stone <mstone@debian.org> - 2022-01-04 19:20 +0100
      Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD piorunz <piorunz@gmx.com> - 2021-12-09 14:30 +0100
  Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD "Alexander V. Makartsev" <avbetev@gmail.com> - 2021-12-09 01:20 +0100
    Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Andy Smith <andy@strugglers.net> - 2021-12-09 02:10 +0100
      Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Jorge P. de Morais Neto <jorge+list@disroot.org> - 2021-12-15 15:50 +0100
        Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Andy Smith <andy@strugglers.net> - 2021-12-16 04:30 +0100
    Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD piorunz <piorunz@gmx.com> - 2021-12-09 11:30 +0100
      Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD "Alexander V. Makartsev" <avbetev@gmail.com> - 2021-12-09 16:30 +0100
        Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD piorunz <piorunz@gmx.com> - 2021-12-09 17:20 +0100
          Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD piorunz <piorunz@gmx.com> - 2021-12-09 18:30 +0100
    Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Jorge P. de Morais Neto <jorge+list@disroot.org> - 2021-12-15 15:40 +0100
  Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD David Christensen <dpchrist@holgerdanske.com> - 2021-12-09 07:10 +0100
    Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Jorge P. de Morais Neto <jorge+list@disroot.org> - 2021-12-14 18:50 +0100
      Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD David Christensen <dpchrist@holgerdanske.com> - 2021-12-15 03:50 +0100
        Re: Why MBR partitioning (was: Reasonably simple setup for 1...) Felix Miata <mrmazda@earthlink.net> - 2021-12-15 04:00 +0100
          Re: Why MBR partitioning (was: Reasonably simple setup for 1...) David Christensen <dpchrist@holgerdanske.com> - 2021-12-15 05:20 +0100
          Re: Why MBR partitioning (was: Reasonably simple setup for 1...) "Thomas Schmitt" <scdbackup@gmx.net> - 2021-12-15 09:10 +0100
  Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Anssi Saari <as@sci.fi> - 2021-12-09 10:40 +0100
    Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Dan Ritter <dsr@randomstring.org> - 2021-12-09 13:10 +0100
    Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Jorge P. de Morais Neto <jorge+list@disroot.org> - 2021-12-14 18:40 +0100
      Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Andrei POPESCU <andreimpopescu@gmail.com> - 2021-12-15 21:30 +0100
  Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD "hdv@gmail" <hdv.jadev@gmail.com> - 2021-12-09 15:10 +0100
    Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Dan Ritter <dsr@randomstring.org> - 2021-12-09 16:10 +0100
      Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD "hdv@gmail" <hdv.jadev@gmail.com> - 2021-12-09 16:50 +0100
        Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Curt <curty@free.fr> - 2021-12-09 18:30 +0100
          Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD David Wright <deblis@lionunicorn.co.uk> - 2021-12-10 06:00 +0100
            Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Darac Marjal <mailinglist@darac.org.uk> - 2021-12-10 10:30 +0100
      Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Stefan Monnier <monnier@iro.umontreal.ca> - 2021-12-10 05:10 +0100
      Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Andrei POPESCU <andreimpopescu@gmail.com> - 2021-12-10 10:40 +0100
        Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Dan Ritter <dsr@randomstring.org> - 2021-12-10 13:40 +0100
          Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Andrei POPESCU <andreimpopescu@gmail.com> - 2021-12-10 14:00 +0100
            Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Dan Ritter <dsr@randomstring.org> - 2021-12-10 15:10 +0100
              Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Charles Curley <charlescurley@charlescurley.com> - 2021-12-11 02:10 +0100
                Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD "Andrew M.A. Cater" <amacater@einval.com> - 2021-12-11 12:30 +0100
          Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Darac Marjal <mailinglist@darac.org.uk> - 2021-12-10 14:20 +0100
    Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD Jorge P. de Morais Neto <jorge+list@disroot.org> - 2021-12-15 16:00 +0100
      Re: Reasonably simple setup for 1TB HDD and 250GB M.2 NVMe SSD "hdv@gmail" <hdv.jadev@gmail.com> - 2021-12-15 16:30 +0100

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