On Wed, May 05, 2004 at 01:31:10PM -0500, Kevin_Gassiot@veritasdgc.com wrote:
We have had problems with any filesystem larger than 1 TB. Although I have been assured that there are no problems with large filesystems, we can create a 1 TB filesystem, and things work fine... create it a megabyte over, and it seems to go fine, but when you start writing to the filesystem, it starts getting I/O errors. I seem to remember getting the answer that fdisk and parted cannot create LUNs larger than 1 TB, so the filesystems built on top of these LUNs have problems. I think I was told that I would have to create LUNs on the arrays smaller than 1 TB, and use LVM to create a logical volume to get the larger size....
I also think this was supposed to be fixed (at least parted, didn't hear anything about fdisk) in an upcoming release ? Do you know if this was fixed in 9.1 ?
I am not aware of any file system problems at 1TB, and I do not think anything specific got fixed. They have limits, but they are much higher than 1TB: 16TB for ext3 and reiserfs, practically unlimited for XFS and JFS which use 64bit block numbers internally. I did test some of these with a holey loopback file and it worked just fine. What I am aware is that there are a few block drivers that have problems. The generic block layer is clean in this regard at least on 64bit systems. On 32bit there is a 2TB limit in 2.4 based kernels; 2.6 supports more even on 32bit. You can check if it is the driver by doing some tests without file system. Use some tool like dd to write a pattern near and crossing the 1TB boundary to the block device, invalidate the buffers using /sbin/blockdev --flushbufs and then try to read it back and verify it. When that fails already it is clearly not the fault of the file system. Often it is not even the driver to blame, but buggy firmware in the controller, where a firmware update may help. One way to work around such driver problems if you are using a RAID box is to configure LUNs <1TB and then use LVM or MD RAID to combine them into a single RAID 0 block device at the Linux side. -Andi