Booted up Slitaz cooking 3, formatted with gparted and installed slitaz

Rebooted, and oh the silence. Its quick of course as Slitaz is running from ram, when the new card comes I’ll try out my xubuntu respin (1.5gb installed)

Thanks for the tips

The write cache on these things are in the 1-4 kB range, so you see a high percentage of “Wa” in ‘top’. If there were a bigger write cache on the devices, I am sure they would work better as a general purpose hard drive.

The kernel is booted with “elevator=noop”, disks mounted with “noatime”, but I was unable to do much with ‘hdparm’ to attempt to control cache. Moving and disabling cache for browsers helped some, as did putting tmp and var/log onto tmpfs mount points (2 GB RAM has lots to spare).

I’d like to move to a compressed file system that reads from CF on boot, caches all changes in RAM, then commits changes back to the CF during shutdown. I just haven’t put in the effort to follow up on the few articles on the web to set this up.

As for disabling the logs, that requires hunting down everything that generates a log, and I haven’t been successful in that yet. Until I get around to finishing that, forcing them all to write to memory instead of the CF card seems to be good enough.

http://www.hjreggel.net/cardspeed/index.html

also, the link below
http://www.thinkwiki.org/wiki/Compact_Flash_boot_drive

suggests that a kernel patch might be necessary to force faster UDMA modes

- it could be worthwile to disable logging altogether. I mean, how often goes something wrong and how often do you peruse log files anyway? Furthermore, if something really goes wrong and isn’t fixed by rebooting you could then always re-enable logging and go bug hunting.

- you could also put the browser cache into memory. Saves some bandwidth and improves your ‘browsing experience’…

# Mount often-written directories in memory to avoid CF card wear
tmpfs		/tmp		tmpfs	noatime,nosuid		0	0
tmpfs		/var/log	tmpfs	noatime			0	0
tmpfs		/var/run	tmpfs	noatime			0	0
tmpfs		/var/lock	tmpfs	noatime			0	0
tmpfs		/var/tmp	tmpfs	noatime			0	0

I also disable the disk cache for Firefox AND set it to zero — I perceived a difference even with the disk cache already disabled.

Finally (of what I can recall off-hand), I use hdparm to force-enable write caching, which doesn’t seem to be enabled by default on CF cards — they’re removable when not used in IDE adapters, so this is a wise default.

The command to enable it is:

sudo hdparm -W 1 /dev/sdX

Where, of course, X is replaced by the assigned label of the CF card drive.

These tweaks all Work happily with a medium-weight Debian setup on a 600MHz-1.6GHz Pentium M laptop . . . still have occasional writes out to disk that spike CPU usage, but it works much better than without these tweaks.

https://lwn.net/Articles/428584/

I need to have a closer look on that too, my 8Gb Sandisk can read at 30MB/s but writes at only 3.0MB/S !!! (on a 1.6GHz system)