Re: mdadm usage

From	deloptes <deloptes@gmail.com>
Newsgroups	linux.debian.user
Subject	Re: mdadm usage
Date	2021-01-02 10:10 +0100
Message-ID	<BsL58-1BB-11@gated-at.bofh.it> (permalink)
References	(6 earlier) <Bs7Kq-1RY-17@gated-at.bofh.it> <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>
Organization	linux.* mail to news gateway

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Andrei POPESCU wrote:

>> Each LSI card has a 6 bay cage attached and I have raided 6x2TB WD RED
>> spinning discs (for data) and 2x1TB WD RED spinning discs (for OS)
> 
> 1TB for OS (assuming RAID1) seems... excessive to me. All my current
> installations are in 10 GiB partitions with only a separate /home.
> 
> Even if I'd go "wild" with several desktops installed (I'm only using
> LXDE), LibreOffice, etc. I'd probably get away with 50 GiB or so. Check
> the output of:
> 
> du -hx --max-depth=1 /
> 
This is true. the root partition is not big - the rest of the space I'll use
for data, but I do not want to use smaller disk, because I will loose two
bays and have the power consumption anyway. I think 1TB is good compromise.
I leave some disk space as spare for LVM and LVM snapshot. I put there the
OS and for example the NFS root/boot stuff or some QEMU machines.

>> I somehow can not convince myself that I need to replace any of these
>> with SSDs.
>> I don't want the cheapest but also not unnecessary expensive drives, I
>> just find it hard to evaluate which drives are reliable.
> 
> The reliability matters much less with RAID1. By the way, the "I" in
> RAID stands for "inexpensive" ;)
> 

For me it does not matter less, as I do not want to spent time. I had it
with Seagate disks before I moved to the WD RED NAS.

> If in doubt buy from two different manufacturers with similar specs.
> RAID devices should whenever possible be from different batches anyway.
> 

I am too old for blind experimenting. This is why I'm asking if someone has
experience with SSD in RAID with consumer grade disks. The once I see are
installed in servers are not available on the consumer market.

>> I saw there are 1TB WD RED SSDs targeting NAS for about €120,-
>> WESTERN DIGITAL WD RED SA500 NAS 1TB SATA (WDS100T1R0A)
> 
> 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?
I already heard one good argument.

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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