1.5TB ext3 partitions - mke2fs problems at 2^31 blocks

Andreas Dilger adilger at clusterfs.com
Mon Oct 31 22:02:17 UTC 2005

On Oct 31, 2005  09:01 +0000, Alex Bligh wrote:
> I am trying to get a 9550SX to support a 1.5TB raid partition. I am unsure
> whether this is a driver problem, or an ext3 problem (as am getting some
> other wierdness detecting LUNs), but...
> fdisk recognizes the disk OK. I make a single extended partition with a
> single 1.5TB logical partition inside it. I then run
> mke2fs -j /dev/sdb
> It gets to writing inode tables, and wants to write 11176 block groups.
> It gets to 3600 (odd) of 11176 block groups fine, then slows to a complete
> crawl (2 secs per write), though strace shows it is fine.
> My suspicious mind says this is 1/3 of the way through the disk, which is
> 2^31 blocks, i.e. where the block number goes negative in a signed
> environment.
> Is there a problem with ext3 supporting more than 2^31 blocks?

We have customers using partitions close to 2TB, with 2.4.21 RHEL3,
2.6.5 SLES9, 2.6.9 RHEL4.

It is concievable that your SCSI card/driver is not doing proper cache
after 1TB or somehow starting to do strange things with the PCI bus
after that point.

Try doing something like:

	dd if=/dev/zero of=/dev/sdb bs=1M &
	sleep 1; while killall -USR1 dd; sleep 1; done

and then plot the dd progress vs time to see if the rate is dramatically
different over time.

Cheers, Andreas
Andreas Dilger
Principal Software Engineer
Cluster File Systems, Inc.

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