Well the swap thing was an easy fix/decision..... I agree that putting swap into an array seems a bit of overkill, however one of the things that can be a problem is mounting swap files into /etc/fstab and then the drive with the swap fails...... My workaround, found on the web and re hashed, is to instead create a 4GB swap partition on each drive then using the following script automount the swaps at boot time using a systemd script. #!/bin/bash # Script for service that autodetects and starts swap partitions for f in $(fdisk -l | grep "Linux swap" | sort | cut -d' ' -f1 | tr '\n' ' '); do swapon $f; done as it only 'finds' swaps on active partitions it prevents boot problems in the case of a dead drive. Due to time constraints I've had to build this using bios_boot and RAID1 /boot/efi and RAID1 /boot partitions for now and the RAID6 partition is currently syncing with a projected finish around 15 hours from now. However given what I've learnt I'm convinced that using initramfs on pre-existing created partitions is the way to go.....RAID6 for all the arrays, including /boot and /boot/efi. Once I've got this migration out of the way and another test box to use I intend to take this a stage further and make it work. Thanks for everyones help and ideas, much appreciated. Tony On 24 May 2015 at 15:57, Mikael Abrahamsson <swmike@xxxxxxxxx> wrote: > On Sun, 24 May 2015, Wols Lists wrote: > >> On 24/05/15 15:06, Mikael Abrahamsson wrote: >>> >>> On Sun, 24 May 2015, Wols Lists wrote: >>> >>>> And if you get read errors, well, aiui, raid won't help here either - >>>> especially with mirrored raid, you just get a read failure. Raid does >>>> NOT give you error recovery unless the drive physically fails, and if >>>> it's a bad block it gets fixed at the disk or disk driver level - well >>>> below the raid driver. >>> >>> >>> You're wrong. In case of a read error from the physical drive on RAID1, >>> RAID5 or RAID6 then the information will be re-created from another >>> drive, and written to the drive that threw a read error. This is the >>> whole point of RAID with parity information. >>> >> Except raid 1 isn't parity ... :-) > > > RAID1 means every drive will have the same information, it's mirrored > between the member disks. What do you think RAID1 is? > >> Personally, I still don't think "raid"ing swap is worth it, though. >> Horses for courses, ram is cheap, and in my circumstances I don't think >> I'd gain anything. > > > You're welcome to believe anything you want, but if you're publically > telling people things that are just not true then you should expect to be > told so. > > You're welcome to tell people to not use SWAP at all, but telling people > RAID1 has no benefit for SWAP because it won't protect you from read erorrs > is just wrong. > > > -- > Mikael Abrahamsson email: swmike@xxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
