Btrfs for /var on SSD

Chowchilla · 2013-01-31 21:32:16

I'll soon be installing Arch again on my system, having just got an SSD to replace the HDD. Deciding on the partition scheme, I'm thinking of largely sticking with my current arrangement (HDD with UEFI/GPT/GRUB2):

/boot/efi, fat32, 512MiB
/boot, ext2, 512MiB
swap, 1GiB
/, ext4, 20GiB
/var, reiserfs, 8GiB
/home, ext4, 100+GiB

Other than adjusting some of the sizes, the only change I think I'll make is the FS choice for /var as resierfs does not support TRIM. I thought ext4 initially but am toying with the idea of btrfs instead (for /var only, / would remain ext4). Would there be a decent performance improvement? And would I need to do anything extra during/after installation? I know use of btrfs *volumes* requires a few things be done, but as I'll just be using a single partition I imagine little will need to be done. I'll probably just use gparted via a live cd/usb before installing to make things easier.

Meyithi · 2013-01-31 21:43:50

If they are all to be on the same disk, I wouldn't bother with an extra /boot, /home or /var - then you can ext4 or btrfs all the things - ext2 for /boot is redundant on a ssd, people used ext2 over ext4 for speed and the fact that journalling isn't required for a partition that hardly changes. With systemd and proper journalling options, the separate /var so as to not fill up your system drive with logs if something should go haywire is also redundant.

Welcome to 2013.

Last edited by Meyithi (2013-01-31 21:44:07)

Stebalien · 2013-02-01 14:10:22

A separate /var can prevent logs from filling up the disk and allows for additional mount options. However, I wouldn't use either reiserfs or btrfs (at the moment). Brtfs is (AFIK) currently slower than ext4. Also, GRUB works with ext4 so you don't need to format /boot with ext2. I would definitely keep the /home partition; it makes reinstalling much easier.

Chowchilla · 2013-02-01 17:02:14

Stebalien wrote:

Also, GRUB works with ext4 so you don't need to format /boot with ext2.

If use ext4 for /boot, is it safe to use noatime? I.e. what I'm wondering is whether GRUB will be adversely affected like some programs are. That aside is there a significant different between using ext4 instead of ext2 for a separate /boot partition.

WRT to /var I think I'll just keep it in / partition as ext4.

olive · 2013-02-01 17:20:45

Chowchilla wrote:

If use ext4 for /boot, is it safe to use noatime? I.e. what I'm wondering is whether GRUB will be adversely affected like some programs are. That aside is there a significant different between using ext4 instead of ext2 for a separate /boot partition.
WRT to /var I think I'll just keep it in / partition as ext4.

The real question is wether you need a separate boot partition. I think the answer is no. You can of course mount with noatime, grub (or whatever boot loader you use) just read the files according to its config. Personnally, I was never convinced by having multiple partitions. This is completely inflexible and you will have difficulties if one of them get full (just notice that Windows, and I think Macosx keep everything on a single partition too) (if you use efi, then you need an efi boot partition). If one really want to prevent log from filling the hard disk, I think that there are more flexible ways that having a separate partition. By the way if /var get full that means that the pacman database cannot grow anymore; so no pacman -Syu anymore. I do see what it really solve in comparaison to having a single partition full of logs that you can easily rm (by the way vi /etc/systemd/journald.conf will probably help more than fdisk on this matter).

Last edited by olive (2013-02-01 17:24:12)

Arch Linux

#1 2013-01-31 21:32:16

Btrfs for /var on SSD

#2 2013-01-31 21:43:50

Re: Btrfs for /var on SSD

#3 2013-02-01 14:10:22

Re: Btrfs for /var on SSD

#4 2013-02-01 17:02:14

Re: Btrfs for /var on SSD

#5 2013-02-01 17:20:45

Re: Btrfs for /var on SSD

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