Performance question for the Linux geeks

[lee n. field]

Lucked into a laptop recently.  Toshiba Satellite, bumped to 3GB.  Came with a Vista license, so it's probably 4-ish years old.  Dual core Turion, 1.9 GHZ I think. 

I set it up with straight up Ubuntu 12.04. 

And, it's pokey.  Ex.: an rsync backup to the main desktop takes way longer, than even from my 1.6 GHz Atom powered netbook.  (Identical script, identical set of folders it's syncing.).

I made a couple choices that i don't usually when I set this up.  The /home partition I formatted ext4 instead of ext3, and I encrypted the my home directory.

I'm thinking either ext4 or the encryption is causing the performance hit.

Anyone know?  Changing either pretty much requires I re-setup everything, which I can certainly do.

[GigaBuist]

Probably the encryption.  The performance differences between ext3 and ext4 are probably negligible, ext4 might even be faster.

But encryption is pretty CPU intensive.  You could measure the difference with something as simple as dd:

dd bs=1024 count=1048576 if=/dev/null of=/home/user/100mb.dat

That'll tell you how long it takes to write to the encrypted area.

Repeat the exercise to an unencrypted area:

dd bs=1024 count=1048576 if=/dev/null of=/tmp/100mb.dat

No need to re-do the whole install though.  You should be able to tar up your home directory, slap it somewhere under /root/, unmount /home, reformat it, and then futz with /etc/fstab to mount a plain ext4 filesystem.

I recently went the other direction (unencrypted /home to encrypted /home) with OpenBSD.  It was pretty painless.  Never done it w/ Linux though.

[bedlamite]

One of these would help too.

[Perd Hapley]

Try Windows.

[zahc]

Interesting. Ext4 isn't slower than Ext3. Does the big laptop have a very slow hard drive? Some laptops have really pokey hard drives, because they can get more capacity for the money that way and capacity sells laptops. I have an encrypted ubuntu install or two, (I have forgot which are encrypted) and I haven't noticed them being slower, though I haven't done a back-to-back on the same machine.

[erictank]

Interesting. Ext4 isn't slower than Ext3. Does the big laptop have a very slow hard drive? Some laptops have really pokey hard drives, because they can get more capacity for the money that way and capacity sells laptops. I have an encrypted ubuntu install or two, (I have forgot which are encrypted) and I haven't noticed them being slower, though I haven't done a back-to-back on the same machine.

Concur - many many older laptop drives are 5400rpm, and pretty pokey by comparison to the 7200rpm drives (to say nothing of solid-state drives) common to desktops. Newer laptops, like the Ivy Bridge-CPU units I'm looking at now (need a new laptop for school work, and I'm gonna get a nice one) are starting to offer not only 7200rpm drives but SSDs, as well - though capacities on the HDDs are still well behind what's available on the physically-larger desktop drives. No surprise, the platters on the 3.5" desktop units have substantially more surface area per platter than the 2.5" units in laptops.

Between drive speed and the possibility of encryption (which I'd think would HAVE to slow things down some), that might do it.

One of these would help too.

Wow - hadn't realized that SSDs were down to under $1/GB, as many on that page are. Sweet!