Fedora 15 SSD optimization

[fedoralinx]

Hi,


I am trying to optimize my SSD for Fedora 15 but ran into a few problems.

I read a couple of guides and most start with changing/adding "discard" to the /etc/fstab.

But the drives listen as per guide start with /dev/sda. I only get a UUID with a long string and can't tell which drive is which.

I have 3 partitions but eventhough I only see 2 drives, or 2 UUIDs that seem relevant.

So what do I do?



Thanks.

[leigh123linux]

Try

blkid

[fedoralinx]

Nice...

And than I just add it I guess? The extra partition.

So that in fstab it will look like:

UUID=50560-jhks9-string-id-etc / etx4 noatime,discard,defaults 1 2

Is that about correct? Or do I make it "1 1" at the end?

And what if a partition doesn't have a mount point which is what the "/" is for I think? I intend to encrypt that partition, if it makes any difference.

[magnusk]

Some reading that might be useful:
http://tombuntu.com/index.php/2008/0...-state-drives/
http://www.zdnet.com/blog/perlow/gee...and-linux/9190

My sda is an SSD and I have added the following to my /etc/rc.local:

# Use deadline scheduler for SSD-disk
echo deadline > /sys/block/sda/queue/scheduler
echo 1 > /sys/block/sda/queue/iosched/fifo_batch
# Write-back caching
hdparm -W1 /dev/sda

and added "discard" to my fstab.

[fedoralinx]

Yes but I really don't wanna go that far. I also read about data loss and life span if you do most of that. The data on the disk is important.

Setting just the partitions will do it for it me. If what I posted earlier is correct?

[leigh123linux]

Originally Posted by fedoralinx

Yes but I really don't wanna go that far. I also read about data loss and life span if you do most of that. The data on the disk is important.

Setting just the partitions will do it for it me. If what I posted earlier is correct?

I use this with my ssd

UUID=91faae69-0fa6-42d8-8d94-1d0070678d8a /                       ext4    defaults,discard        1 1

I would also recommend moving /tmp to RAM

none                    /tmp                    tmpfs   defaults        0 0

[fedoralinx]

Yes that seems best.

Should I do that for the second partition (add it) and swap partition as well?

[leigh123linux]

Originally Posted by fedoralinx

Yes that seems best.

Should I do that for the second partition (add it) and swap partition as well?

I believe trim is automatic with swap

http://forums.fedoraforum.org/showthread.php?t=256068

[stevea]

UUID=50560-jhks9-string-id-etc / etx4 noatime,discard,defaults 1 2

You don't need the 'defaults' string if there is any other option - it's just a placeholder
noatime is a good idea for any file system.
Nearly every Linux filesystem you might want to consider takes the "discard" option including vfat, btrfs, ext3/4, xfs.

UUID=50560-jhks9-string-id-etc / ext4 noatime,discard 1 2

Yes ,TRIM is automatic with swap and has been for a while.
Recently (~2.6.36 IIRC) LVM supports TRIM passthrough.


FWIW - IF you've been using your disk without the TRIM option, then any blocks deleted from the file system are not known to be free by the drive. So on a clean install all the writes are fine, but when you start upgrading packages ...or otherwise deleting files - the block go into limbo. It's not a big deal for a few percent of the disk size - but it may be a long long time before those blocks ar recouped through garbage collection.

[fedoralinx]

Oh ok. I will do that.

Should I add the last partition too, eventhough it has no mount point? It shows up in "blkid" but not /etc/fstab.

And I had a problem doing "dd if=/dev/urandom of=/dev/sda". It seems to stall before finished. "dd: Writing ... Out Of Space ...". Eventhough the partition is 10gb it only wrote 1500mb to it. It said so in its report.