Disk write speed
 

I've been using linux for a while now, and I've noticed that the disk write speed seems significantly slower then in Windows.

I'm using FC3 with an ext3 file system. Is there some optimization I can make to speed things up?

Is dma active on the drive?

yes it is

Run hdparm and let us know the results.

-twantrd

I ran "/sbin/hdparm -t /dev/hdb" and got the following results.

/dev/hdb:
Timing buffered disk reads: 74 MB in 3.05 seconds = 24.29 MB/sec

Hmmm, these are my results:

/dev/hdb:
Timing buffered disk reads: 154 MB in 3.02 seconds = 50.99 MB/sec

Can you display the settings on the disk?

-twantrd

The disk I'm talking about only has a 2MB buffer. The 8MB disk I have has the following results:

/dev/hda:
Timing buffered disk reads: 124 MB in 3.04 seconds = 40.77 MB/sec

As a test, I timed writing a 346MB file. It took exactly 60 seconds. Does this seem slow to anybody else? This is on the 2MB drive.

The utility hdparm only shows raw speed. It does not count for speed of the filesystem. Also cache has nothing to do with the throughput of the hard drive. Cache is only there when multiple files are needed to be access at once. The throughput depends on bus, PCI controller, cable, hard drive, and filesystem. With hdparm I get over 54 megabytes per second with an IBM/Hitachi 180GXP 120 GB hard drive connected to a Highpoint HPT372 controller. The filesystem that I'm using on that drive is XFS. It can create a few gigabyte files in about 30 to 40 secs even though it had about 10 GB of space left. I tried bonnie and bonnie++ but the results that it gave was not accurate. I used dd and used /dev/random to make 1 megabyte file. I then copy multiple of these files to combine them in a 100 megabyte file. The ext3 filesystem is slow compared to many filesystems. You can try using ReiserFS or XFS if you want to increase the speed of the hard drive. I do not suggest using Reiser4 because it can be unreliable at times.

We weren't doing cache timings. We were doing device read timings. Unless I'm mistaken. I looked at the man pages and it shows:

-t perform device read timings
-T perform cache read timings


-twantrd

occuda kept on saying about the 2 MB cache versus the 8 MB cache during the hdparm tests. Did you read my post or did you skimed it. To me you skimed my post.

-T is buffer-cache
-t is buffered

Both are solidstate memory. Which values you should look is up to you. hdparm should only be used to just give estimates.

Woah, my fault. I read your post and somehow thought something else of it. My bad.

-twantrd

I get the following results , can i fix it or somehow improve it . MY hard disk is a western digital 8mb cache .
Im on slackware 10.1 2.6.10 kernel


Thank you