Thanks Craig,
I have elected to start with a Ubuntu 18.04 LTS desktop install.
The Raid drives were picked up, ie are available, but does the balance command need to be issued again?
I had two lines to set up the raid and balance them at the start. I suspect that without those commands only one drive will be written to.
Thanks for your assistance
Andrew
Sent from Samsung tablet.
-------- Original message --------
From: Craig Sanders via luv-main <luv-main@luv.asn.au>
Date: 18/1/20 12:59 pm (GMT+10:00)
To: luv-main@luv.asn.au
Subject: Re: Rebuild after disk fail
> I recently experienced an SSD failure, and so I have purchased another to
> set up my system again. I received some substantial help from this list
> early in 2019 to build my machine with this SSD as / and /home under Ubuntu
> 18.04 with two x 2Tb conventional drives in RAID for storing my work, all
> are running btrfs.
You lost your home dir and the data in it when your SSD failed Because your
rootfs and /home on the SSD doesn't have any redundancy (i.e. it was a single
partition, with no RAID). I strongly recommend setting up a cron job to
regularly snapshot it (at least once/day) and do a 'btrfs send' of that
snapshot to a sub-volume of your /data filesystem.
That way you won't lose much data from that partition if your SSD dies again
- you can retrieve it from the last snapshot backup, and will only lose any
changes since then.
If your / and /home are on separate partitions (or btrfs sub-volumes) you will
need to do this for both of them.
(if you weren't running btrfs on /, you could do this with rsync instead of
'btrfs send', but rsync would be a lot slower)
IME, drives are fragile and prone to failure. It's always best to make plans
and backup procedures so that WHEN (not IF) a drive fails, you don't lose
anything important...or, at least, minimise your losses.
Also, remember that RAID is not a substitute for backup so you should
regularly backup your /data filesystem to tape or other drives. Ideally,
you should try to have an off-site backup in case of fire/flood/etc (e.g.
backup to an external USB drive and store it at your office, lawyer's safe, a
friend's house or somewhere. Have at least two of these so you can rotate the
offsite backups).
> After the machine was running I was asked if I had set up the machine using
> Ubuntu Server, I hadn't, because at that time I didn't see those options.
>
> I am thinking, then, for this build, perhaps I should set it up using Ubuntu
> Server. I will need to get my system to recognise the RAID drives as well.
If the installer doesn't automatically detect your /data btrfs filesystem and
add it to /etc/fstab, it's easy enough to add it yourself.
> So before I jump in the deep end again, are there any "gotchas" of which I
> should be aware.
>
> Will the server version make life more reliable?
the only significant difference between the server and desktop versions of
ubuntu are the packages which are installed by default. e.g. the desktop
version installs a whole bunch of desktop stuff (X, desktop environment and
GUI apps, etc) that the server version doesn't. Otherwise, they're the same -
same kernel, same libc and other standard system libraries, etc.
craig
--
craig sanders <cas@taz.net.au>
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