I've noticed a lot of the same things actually - I was using an Ubuntu
LiveUSB for a while, with persistent storage, and that would be just
brutal in terms of any disk I/O.
Actually it was with the latest one, Hardy Heron, so if anyone is using
that on a flash filesystem, be sure to have _loads_ of ram, a magnetic
disk swap, or be prepared to do a lot of extra configuration to prevent
disk writes.
Thanks for the tips,
Chris
Joshua ChaitinPollak wrote:
Here's a response from a co-worker who has done some work on his EEE pc:
Interesting stuff. As I understand it, with the Asus I've read that
they've basically leveraged a write-balancing algorithm at the flash
firmware level so that they fairly evenly distribute updates across
the flash. So, bottom line, Asus doesn't worry too much about burn-in.
They even ship with a writable ext3 partition, which would be really
detrimental to disk due to the "duplicate write" overhead of
continuous journaling (presumably in a fixed area of the disk?) if it
weren't for the balancing logic.
W.r.t. keeping log size down, I think Asus's build of Xandros has
turned off a bunch of debug-level logging within most of their
packages (at build time?) and as such doesn't really demand much disk
for logging operations, etc.
Same may apply to a Gentoo install - compile your stuff to not log at
debug level (or turn off in syslog?) and you should be fine...
One thing that I did observe when I started using external ext2/ext3
partitions on the SD card slot was extremely lethargic writes. This
was due to the fact that SD cards with ext2/ext3 partitions were being
mounted with the 'sync' flag. From what I have read, this is extremely
slow and extremely detrimental to flash. This is because every byte
would be written individually, but due to the way flash works, you
write a block at once. So, say the block size is 192 bytes... To write
192 bytes with sync on could cause 192 flashes of the block (or some
fraction/multiple of 192). With async enabled (sync not enforced) the
OS is able to cache up some data before writing, dramatically
increasing the likelihood that it will have enough data to fill the
block in 1 single write operation.
So, another tip for Gentoo users - make sure any ext2/ext3 flash
partitions are mounted async (default) - not with the sync flag set
like Xandros does by default with the SD card slot...
-Andrew
On Apr 17, 2008, at 11:12 AM, Christian Bricart wrote:
Joshua ChaitinPollak wrote:
[..]
I don't know how you'd handle things like Firefox's cache, I don't
know any way to reduce its writes or redirect them out of your profile.
http://www.mozilla.org/catalog/end-user/customizing/briefprefs.html
http://kb.mozillazine.org/Browser.cache.disk.parent_directory
drop a file in /usr/lib/mozilla-firefox/defaults/pref/ with content like:
+---
| pref("browser.cache.disk.parent_directory", "/tmp");
+---
or even:
+---
| pref("browser.cache.disk.enable", false);
+---
Christian
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