[asterisk-users] Asterisk RT on Disk On Module Performance and Durability

[Brian Candler]

On Fri, Oct 06, 2006 at 05:10:34PM -0500, Erick Perez wrote:
>    Example: if I setup system XYZ with asterisk, then load this magical
>    utility/procedure that counts how many writes the filesystem has done
>    to / or to /,/tmp,/var and after 24 hours the utility/procedure says:
>    10thousand writes, then, I will do

It's not so much magic. You're looking for "iostat", see
http://www.redhat.com/docs/manuals/linux/RHL-9-Manual/admin-primer/s1-resource-rhlspec.html
http://www.redhat.com/magazine/011sep05/features/tools/

I'm no expert here, but for flash drives it might not be quite so simple.
You may need to think about how many times the *same* block is overwritten.

If you use a filesystem which does "wear levelling" (such as jffs2), it will
spread these operations across the whole device. And maybe your flash device
does wear levelling of its own, in which case you don't have to worry.

http://en.wikipedia.org/wiki/Flash_memory
http://en.wikipedia.org/wiki/Wear_levelling

Then you just need to check whether your device spec for 2 million R/W
cycles is the value per block, or the total value spread across the whole
device. Since the latter gives the higher number, then that's probably what
the manufacturer has quoted.

HTH,

Brian.