From mboxrd@z Thu Jan  1 00:00:00 1970
From: =?UTF-8?Q?Micha=C5=82?= Sawicz <michal@sawicz.net>
Subject: Re: Best strategy to incrementally replace smaller HDDs [success
 story]
Date: Tue, 27 Sep 2011 10:37:48 +0200
Message-ID: <1317112668.2758.43.camel@michal-laptop>
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	 <20110909131351.GA25347@cthulhu.home.robinhill.me.uk>
	 <1315578025.14468.18.camel@michal-laptop>
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To: Robin Hill <robin@robinhill.me.uk>
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Thanks again for all the pointers, I will now describe my workflow that
got me going with the new drives!

I'll try and do some ASCII-art [=3D=3D=3D used space, --- space (not drives=
)
used for parity].


1. initial situation
   -----------------
    ~~1TB~~
sda |=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D|
sdb |=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D|
sdc |=3D=3D=3D=3D=3D|
sdd |=3D=3D=3D=3D=3D|
sde |=3D=3D=3D=3D=3D|
sdf |=3D=3D=3D=3D=3D|
sdg |=3D=3D=3D=3D=3D|
sdh |=3D=3D=3D=3D=3D|
sdi |-----|
sdj |-----|

md1       |=3D=3D=3D=3D=3D|             -  2 x 1TB RAID0 =3D=3D 2TB
md2 |=3D=3D=3D=3D=3D|                   - 10 x 1TB RAID6 =3D=3D 8TB


2. added 4 x 2TB drives
   --------------------
sdk             |           |
sdl             |           |
sdm             |           |
sdn             |-----------|

md3             |           | -  5 x 2TB RAID6 =3D=3D 6TB (degraded)


3. moved part of md2 data onto md3
   ----------------------------------
sda |     =3D=3D=3D=3D=3D=3D|
sdb |     =3D=3D=3D=3D=3D=3D|
sdc |=3D=3D=3D=3D=3D|
sdd |=3D=3D=3D=3D=3D|
sde |=3D    |
sdf |     |
sdg |     |
sdh |     |
sdi |-----|
sdj |-----|
sdk             |=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D|
sdl             |=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D|
sdm             |=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D|
sdn             |-----------|

md1       |=3D=3D=3D=3D=3D|             -  2 x 1TB RAID0 =3D=3D 2TB
md2 |=3D=3D   |                   - 10 x 1TB RAID6 =3D=3D 8TB
md3             |=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D| -  5 x 2TB RAID6 =3D=3D=
 6TB (degraded)


4. shrunk and removed drives from md2
   ----------------------------------
sda |     =3D=3D=3D=3D=3D=3D|
sdb |     =3D=3D=3D=3D=3D=3D|
sdc |=3D=3D=3D=3D=3D|
sdd |=3D=3D=3D=3D=3D|
sde |=3D    |
sdf |-----|
sdg                         |     |
sdh                         |     |
sdi                         |     |
sdj                         |     |
sdk             |=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D|
sdl             |=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D|
sdm             |=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D|
sdn             |-----------|

md1       |=3D=3D=3D=3D=3D|             -  2 x 1TB RAID0 =3D=3D 2TB
md2 |=3D=3D=3D=3D |                   -  5 x 1TB RAID6 =3D=3D 3TB (degraded=
)
md3             |=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D| -  5 x 2TB RAID6 =3D=3D=
 6TB (degraded)


5. new arrays to free the old 2TB drives
   and create an additional member for md4
   ---------------------------------------
sda             |=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D|
sdb             |=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D|
sdc |=3D=3D=3D=3D=3D|
sdd |=3D=3D=3D=3D=3D|
sde |=3D    |
sdf |-----|
sdg       |=3D=3D=3D=3D=3D|
sdh       |=3D=3D=3D=3D=3D|
sdi             |=3D=3D=3D=3D=3D|
sdj                   |=3D=3D=3D=3D=3D|
sdk             |           |
sdl             |           |
sdm             |-----------|
sdn             |-----------|

md4             |           | -  4 x 1TB RAID10 =3D=3D 2TB (degraded)
md1       |=3D=3D=3D=3D=3D|             -  2 x 1TB RAID0 =3D=3D 2TB
md2 |=3D=3D=3D=3D |                   -  5 x 1TB RAID6 =3D=3D 3TB (degraded=
)
md3             |=3D=3D=3D=3D=3D=3D=3D    | -  7 x 2TB RAID6 =3D=3D 10TB


6. Moved rest of the data from md2,
   dropped it and replaced a disk in md4
   -------------------------------------
sda             |=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D|
sdb             |=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D|
sdc             |=3D=3D=3D=3D=3D|
sdg       |=3D=3D=3D=3D=3D|
sdh       |=3D=3D=3D=3D=3D|
sdj                   |=3D=3D=3D=3D=3D|
sdk             |=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D|
sdl             |           |
sdm             |-----------|
sdn             |-----------|

md4             |           | -  4 x 1TB RAID10 =3D=3D 2TB (degraded)
md1       |=3D=3D=3D=3D=3D|             -  2 x 1TB RAID0 =3D=3D 2TB
md3             |=3D=3D=3D=3D=3D=3D=3D=3D=3D  | -  7 x 2TB RAID6 =3D=3D 10T=
B


And it only took two weeks! ;)

And again, thanks for all the pointers I got on the list, it all
happened without any data loss.
--=20
Micha=C5=82 (Saviq) Sawicz <michal@sawicz.net>

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