Hello.
This is a comment from block_alloc.c:
/*
* SPACE RESERVED FOR UNLINK/TRUNCATE
*
* Unlink and truncate require space in transaction (to update stat data, at
* least). But we don't want rm(1) to fail with "No space on device" error.
*
* Solution is to reserve 5% of disk space for truncates and
* unlinks. Specifically, normal space grabbing requests don't grab
space from
* reserved area. Only requests with BA_RESERVED bit in flags are allowed to
* drain it. Per super block delete mutex is used to allow only one
* thread at a time to grab from reserved area.
*
* Grabbing from reserved area should always be performed with BA_CAN_COMMIT
* flag.
*
*/
Ignatich wrote:
Reiser4 reserves roughly 5% of partition size for it's internal use.
This space can be tens of gigabytes for modern hard disks, and unlike
ext2 reserve cannot be used even by root in any way.
use compression ( http://dev.namesys.com/GettingStartedCryptcompress )
and you will save more then 5% of partition size
I changed reserved block count in super.c to be 1% instead of 5%,
formatted a test drive in reiser4 and stress tested it by copying many
small or few huge files to almost full disk. Everything was working fine.
you will encounter problems when using serious workload
It there a reason for this reserve to be so big?
this value is empirical: it is impossible to estimate this precisely
Thanks.
