Partitioning strategy for a system on external USB2 disk ?

xaviermiller

Hello,

I run Gentoo on a Raspberry Pi, the system is running on a 2 Tb USB external HDD (the SD card is only used to boot the kernel and switch to the hard disk). The disk is also used as NAS through the Raspberry Pi. The board runs also a print server.

For now, I have 2 partitions : 1 for / in ext2 and 1 for the swap.

But when the raspberry pi restart after a failure, it took about 2 hours to resume because of fsck on the whole big partition.

My idea is to have a smaller partition for the system and a bigger for the NAS, so that the system will resume faster, and let the fsck of the NAS data later, when the server is up and running.

So my question is : do you think it will be faster that way ? I presume I have to disable the auto-mounting of the NAS partition, and let it done later (in local service for example). Is there a faster filesystem for recoveries? I would prefer a filesystem that don't add too much I/O overhead because the slow processor and I/O's (USB2). Isn't better I use ext4 for example?

Kind Regards,
_________________
Kind regards,
Xavier Miller

NeddySeagoon · Posted: Thu Jun 19, 2014 8:03 pm Post subject:

XavierMiller,

Convert the ext2 fs to ext3 and have a journal.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

xaviermiller · Posted: Thu Jun 19, 2014 8:04 pm Post subject:

And is it better to have many partitions ?
_________________
Kind regards,
Xavier Miller

NeddySeagoon · Posted: Thu Jun 19, 2014 8:14 pm Post subject:

XavierMiller,

Many partitions is a double edged sword. It makes it difficult to move space around but even ext2 will fsck faster on a smaller partition.
A journaled filesystem does not prevent fsck from running - it runs every 30 mounts or so, even on ext4

Maybe LVM can help?
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

xaviermiller · Posted: Thu Jun 19, 2014 8:17 pm Post subject:

I don't think LVM would help. I can reserve 16G-32G for / and the rest for data.

Why don't you recommand ext4? because features needing more resources?
_________________
Kind regards,
Xavier Miller

NeddySeagoon · Posted: Thu Jun 19, 2014 8:26 pm Post subject:

XavierMiller,

Converting ext2 to ext3 is trivial. You use tune2fs to add the journal and mount the filesystem as ext3.
You get a file called .journal.

You can even go back to ext2 if you want to.

I'm unsure of the upgrade path to ext4 and unless you want extents and barriers, it has little to offer over ext3.
_________________
Regards,

NeddySeagoon

Computer users fall into two groups:-
those that do backups
those that have never had a hard drive fail.

xaviermiller · Posted: Thu Jun 19, 2014 8:28 pm Post subject:

OK thank you! I will then pass to 2 ext3 partitions

_________________
Kind regards,
Xavier Miller

xaviermiller · Posted: Sun Jun 22, 2014 7:19 pm Post subject:

It's done, I have 2 ext3 partitions, the system is more reactive on boot

_________________
Kind regards,
Xavier Miller