Re: mdadm usage

From	Andrei POPESCU <andreimpopescu@gmail.com>
Newsgroups	linux.debian.user
Subject	Re: mdadm usage
Date	2021-01-02 11:30 +0100
Message-ID	<BsMkx-2m0-9@gated-at.bofh.it> (permalink)
References	(5 earlier) <Bs7U5-1V9-5@gated-at.bofh.it> <Bs8dr-21K-11@gated-at.bofh.it> <BsAMq-37V-9@gated-at.bofh.it> <BsKC6-1b2-1@gated-at.bofh.it> <BsL58-1BB-11@gated-at.bofh.it>
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On Sb, 02 ian 21, 10:05:11, deloptes wrote:
> Andrei POPESCU wrote:
> > 
> > The speed gain of SSD vs. spinning discs for the OS is hard to describe.
> > Think jet aircraft vs. car.
> > 
> > I've done this for a laptop (partially out of necessity, after I dropped
> > it) and it was like buying a new system, even if the processor was
> > already significantly outdated at the time (one of the first non-Itanium
> > Intel 64 bit processors).
> 
> Yes, but as mentioned the LSI I use in the server are SATA2 so it will stick
> to bandwidth throughput of 300MB/s - does it make sense to replace the good
> WD RED spinning disks with SSD?

Yes.

As far as I recall the laptop I mentioned above had SATA I only 
(definitely at least one SATA generation below the capability of the 
SSD) and the usability increase was huge.

When discussing "OS speed" the important difference between SSDs and 
HDDs is the random read speed, which is orders of magnitude higher.

Just compare for yourself the random read speed of your drives with the 
theoretical speed of SATA II. Now look at the random read speeds of some 
consumer SATA drives.

Even if the RAID1 helps with random read speeds, a single SSD will run 
circles around it. Over SATA II.

Sequential read / write speed matters only when copying large[1] files 
around. With smaller file sizes spinning drives waste a lot of time 
seeking. Add file fragmentation on top.

[1] for the purposes of this discussion let's consider "large" files to 
be files bigger than what your drives can transfer per second in real 
life, including the seek times. I'm hoping other readers will correct me 
if my assumption is way of.

Kind regards,
Andrei
-- 
http://wiki.debian.org/FAQsFromDebianUser

Thread

mdadm usage "Thomas A. Anderson" <thomas.anderson@little-beak.com> - 2020-12-29 08:10 +0100
  Re: mdadm usage Reco <recoverym4n@enotuniq.net> - 2020-12-29 08:30 +0100
    Re: mdadm usage deloptes <deloptes@gmail.com> - 2020-12-29 09:40 +0100
  Re: mdadm usage Felix Miata <mrmazda@earthlink.net> - 2020-12-29 08:50 +0100
    Re: mdadm usage basti <mailinglist@unix-solution.de> - 2020-12-29 09:40 +0100
      Re: mdadm usage "Thomas A. Anderson" <thomas.anderson@little-beak.com> - 2020-12-29 21:40 +0100
        Re: mdadm usage Linux-Fan <Ma_Sys.ma@web.de> - 2020-12-30 00:00 +0100
        Re: mdadm usage deloptes <deloptes@gmail.com> - 2020-12-30 02:00 +0100
          Re: mdadm usage Michael Stone <mstone@debian.org> - 2020-12-30 02:30 +0100
            Re: mdadm usage deloptes <deloptes@gmail.com> - 2020-12-30 09:20 +0100
            Re: mdadm usage Jesper Dybdal <jd-debian-user@dybdal.dk> - 2020-12-30 14:40 +0100
              Re: mdadm usage Andy Smith <andy@strugglers.net> - 2020-12-30 15:00 +0100
                Re: mdadm usage Jesper Dybdal <jd-debian-user@dybdal.dk> - 2021-01-02 14:40 +0100
              mdadm usage Nicholas Geovanis <nickgeovanis@gmail.com> - 2020-12-30 15:10 +0100
                Re: mdadm usage Nicholas Geovanis <nickgeovanis@gmail.com> - 2020-12-30 15:10 +0100
                Re: mdadm usage deloptes <deloptes@gmail.com> - 2020-12-30 21:50 +0100
                Re: mdadm usage Michael Stone <mstone@debian.org> - 2020-12-30 22:40 +0100
                Re: mdadm usage deloptes <deloptes@gmail.com> - 2020-12-30 23:20 +0100
                Re: mdadm usage Andy Smith <andy@strugglers.net> - 2020-12-31 00:30 +0100
                Re: mdadm usage rhkramer@gmail.com - 2020-12-31 13:30 +0100
                Re: mdadm usage Michael Stone <mstone@debian.org> - 2020-12-31 15:20 +0100
                Re: mdadm usage Andy Smith <andy@strugglers.net> - 2020-12-31 15:30 +0100
                Re: mdadm usage Reco <recoverym4n@enotuniq.net> - 2020-12-31 15:50 +0100
                Re: mdadm usage Andy Smith <andy@strugglers.net> - 2020-12-31 16:10 +0100
                Re: mdadm usage Reco <recoverym4n@enotuniq.net> - 2020-12-31 16:20 +0100
                Re: mdadm usage Andy Smith <andy@strugglers.net> - 2020-12-31 16:40 +0100
                Re: mdadm usage deloptes <deloptes@gmail.com> - 2021-01-01 23:10 +0100
                Re: mdadm usage Andrei POPESCU <andreimpopescu@gmail.com> - 2021-01-02 09:40 +0100
                Re: mdadm usage deloptes <deloptes@gmail.com> - 2021-01-02 10:10 +0100
                Re: mdadm usage Andrei POPESCU <andreimpopescu@gmail.com> - 2021-01-02 11:30 +0100
                Re: mdadm usage Linux-Fan <Ma_Sys.ma@web.de> - 2021-01-02 14:50 +0100
                Re: mdadm usage deloptes <deloptes@gmail.com> - 2021-01-02 16:40 +0100
                Re: mdadm usage Linux-Fan <Ma_Sys.ma@web.de> - 2021-01-02 18:10 +0100
                Re: mdadm usage The Wanderer <wanderer@fastmail.fm> - 2021-01-02 10:40 +0100
                Re: mdadm usage Andrei POPESCU <andreimpopescu@gmail.com> - 2021-01-02 12:00 +0100
                Re: mdadm usage The Wanderer <wanderer@fastmail.fm> - 2021-01-02 12:30 +0100
                Re: mdadm usage Andrei POPESCU <andreimpopescu@gmail.com> - 2021-01-02 12:50 +0100
                Re: mdadm usage Andrei POPESCU <andreimpopescu@gmail.com> - 2021-01-02 13:10 +0100
                Re: mdadm usage The Wanderer <wanderer@fastmail.fm> - 2021-01-02 14:20 +0100
                Re: mdadm usage The Wanderer <wanderer@fastmail.fm> - 2021-01-02 14:10 +0100
                Re: mdadm usage deloptes <deloptes@gmail.com> - 2021-01-02 12:50 +0100
          Re: mdadm usage "Thomas A. Anderson" <thomas.anderson@little-beak.com> - 2020-12-30 11:50 +0100
            Re: mdadm usage "Alexander V. Makartsev" <avbetev@gmail.com> - 2020-12-30 13:30 +0100
            Re: mdadm usage Dan Ritter <dsr@randomstring.org> - 2020-12-30 13:30 +0100
            Re: mdadm usage Andy Smith <andy@strugglers.net> - 2020-12-30 15:00 +0100
            Re: mdadm usage deloptes <deloptes@gmail.com> - 2020-12-30 22:10 +0100
              Re: mdadm usage Nicholas Geovanis <nickgeovanis@gmail.com> - 2020-12-31 00:00 +0100
        Re: mdadm usage Andrei POPESCU <andreimpopescu@gmail.com> - 2020-12-30 09:10 +0100
      Re: mdadm usage Dan Ritter <dsr@randomstring.org> - 2020-12-30 04:00 +0100
  Re: mdadm usage Andy Smith <andy@strugglers.net> - 2020-12-29 14:20 +0100
    Re: mdadm usage mick crane <mick.crane@gmail.com> - 2020-12-29 16:40 +0100
      Re: mdadm usage "Alexander V. Makartsev" <avbetev@gmail.com> - 2020-12-29 20:40 +0100
      Re: mdadm usage Andy Smith <andy@strugglers.net> - 2020-12-30 14:40 +0100
        Re: mdadm usage The Wanderer <wanderer@fastmail.fm> - 2020-12-30 14:50 +0100
        Re: mdadm usage mick crane <mick.crane@gmail.com> - 2020-12-30 18:00 +0100
          Re: mdadm usage Andrei POPESCU <andreimpopescu@gmail.com> - 2020-12-30 19:40 +0100

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