Hi Craig, Yes, the problem was my Motherboard would not handle enough disks, and we did Format sdc with btrfs and left the sdb alone so that btrfs could arrange things between them. I was hoping to get an understanding of how the RAID drives remembered the "Balance" command when the the whole of the root filesystem was replaced on a new SSD. I thought that control would have rested with /etc/fstab. How do the drives know to balance themselves, is there a command resident in sdc1? My plan is to have auto backups, and given that my activity has seen an SSD go down in 12 months, maybe at 10 months I should build a new box, something which will handle 64Gb RAM and have a decent Open Source Graphics driver. And put the / on a pair of 1Tb SSDs. Many thanks Andrew On 18/1/20 6:44 pm, Craig Sanders via luv-main wrote:
On Sat, Jan 18, 2020 at 02:14:46PM +1100, Andrew McGlashan wrote:
Just some thoughts....
Way back, SSDs were expensive and less reliable than today.
Given the cost of SSDs today, I would consider even RAIDING the SSDs. If it's physically possible to install a second SSD of the same storage capacity or larger then he absolutely should do so. I vaguely recall suggesting he should get a second SSD for the rootfs ages ago, but my understanding / assumption was that there was only physical space and connectors for one SSD in the machine.
The 'btrfs snapshot' + 'btrfs send' suggestion was just a way of regularly backing up a single-drive btrfs filesystem onto his raid-1 btrfs array so that little or nothing was lost in case of another drive failure. It's less than ideal, but a LOT better than nothing.
I personally would never use anything less than RAID-1 (or equivalent, such as a mirrored pair on zfs) for any storage. Which means, of course, that I'm used to paying double for my storage capacity - i can't just buy one, I have to buy a pair. Not as a substitute for regular backups, but for convenience when only one drive of a pair has died.
Drives die, and the time & inconvenience of dealing with that (and the lost data) cost far more than the price of a second drive for raid-1/mirror.
craig
-- craig sanders <cas@taz.net.au> _______________________________________________ luv-main mailing list luv-main@luv.asn.au https://lists.luv.asn.au/cgi-bin/mailman/listinfo/luv-main