Hi All,
Here is my fstab after the install, it seems that my two "RAID" drives
are just "dwellers on the threshold" as they do not appear in fstab.
alg@andrewg:~$ sudo cat /etc/fstab
[sudo] password for alg:
# /etc/fstab: static file system information.
#
# Use 'blkid' to print the universally unique identifier for a
# device; this may be used with UUID= as a more robust way to name devices
# that works even if disks are added and removed. See fstab(5).
#
# <file system> <mount point> <type> <options> <dump> <pass>
# / was on /dev/sda3 during installation
UUID=2dfcd965-625b-47d5-a267-b02276320922 / btrfs
defaults,subvol=@ 0 1
# /home was on /dev/sda3 during installation
UUID=2dfcd965-625b-47d5-a267-b02276320922 /home btrfs
defaults,subvol=@home 0 2
# swap was on /dev/sda2 during installation
UUID=b2c6d1c4-4b94-4171-954e-9f5d56704514 none swap
sw 0 0
alg@andrewg:~$
Are these two following commands OK to apply to drives that were
balanced previously and hold data?
sudo btrfs device add -f /dev/sdc1 /data
sudo btrfs ballance start -dconvert=raid1 -mconvert=raid1 /data
and will issuing those commands write that into fstab?
Many thanks
Andrew
On 18/1/20 12:59 pm, Craig Sanders via luv-main wrote:
On Fri, Jan 17, 2020 at 11:36:29AM +1100, Andrew Greig wrote:
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 <c...@taz.net.au>
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