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View Full Version : [ubuntu] External eSATA hard drive - slow transfers on fat32, fast on ext3



anthropodeus
April 29th, 2009, 11:27 PM
I have a ~500GB external HDD connected to my laptop via eSATA. There are two partitions on it: a small one that is fat32 and a large one that is ext3.

files transfer to the ext3 partition at normal eSATA speeds - about 33MB/s. but the transfer speed to the fat32 partition is only around 10MB/s max, and usually slows to around 6MB/s as the transfer proceeds.

if i change the options from the ext3 partition from "relatime" (the default) to "rw,auto,user,sync" so that i can unmount it without going through root, the transfer speeds to the ext3 partition ALSO slow down to ~10MB/s.

so what is it in the "relatime" default that makes mount recognize the connection as full eSATA? and how can i make the fat32 partition transfer at full eSATA speed?

here's the relevant stuff from /etc/fstab:



# <file system> <mount point> <type> <options> <dump> <pass>
#
#External Hard Drive:
#
# /media/Archive was on /dev/sdb3 during installation.
UUID=2d840736-429e-4984-9f75-7ad1c532c9b0 /media/Archive ext3 relatime 0 2
# /media/ExternalAudio was on /dev/sdb2 during installation
UUID=49E2-61B0 /media/ExternalAudio vfat rw,noauto,user,sync,shortname=mixed,utf8 0 1

logos34
April 30th, 2009, 01:26 AM
I wonder if it's the way Hal is mounting the vfat partition (vs. an interface issue). Related discussion here (http://ubuntuforums.org/archive/index.php/t-793688.html) (but concerned with USB). Maybe add the fstab mount options async and flush

atime vs. noatime and relatime is explained here (http://blogs.koolwal.net/2009/01/30/installing-linux-on-usb-part-4-noatime-and-relatime-mount-options/). (speed diff in ext3 is due to atime/sync excessive disk writes)

There was another article explaining noatime and relatime that I read some time back (when I was trying to eliminate constant disk activity), but I can't seem to find it now. hmm