Re: ext4 64bit (disk >16TB) question

Goswin von Brederlow
2008-07-15T16:13:20Z

Ric Wheeler <rwheeler@redhat.com> writes:

> How long would you wait for something like fsck to run to completion
> before you would need to go to back up tapes? 6 hours? 1 day? 1 week
> ;-) ?

Backup? What are backups? :))

A hardware raid6 resync takes about 16h. A Software raid6 (over 6
hardware raid6) resync takes 1-2 days.

With lustre the fsck has to be done on the MDT (meta data target) to
build a database file and on all the OST (object storage target). So
there is some parallelization in the system.

But each OST, if we get ext4 64bit working, would be 28TB. I would
assume days for an fsck run. Weeks would not be good and less than a
day is totaly unrealistic.

But a few days for an fsck of 400-800TB filesystem isn't so
bad. Reading that amount from backup will take ages too, if you even
have one.

MfG
Goswin