uname ¨Ca Linux RANC01 2.6.26-2-amd64 #1 SMP Tue Jan 12 22:12:20 UTC 2010 x86_64 GNU/Linux I successfully created the JFS file system on the huge logical volume (consists of two equal-sized RAID 6 virtual disks, totally about 48T) and mounted the volume. When I tried to make directory on it, it complained about file io error. The following is excerpted from kern.log: ... Mar 30 12:00:33 RANC01 kernel: [ 6758.339211] scsi 4:2:0:0: Direct-Access DELL PERC 6/E Adapter 1.22 PQ: 0 ANSI: 5 Mar 30 12:00:33 RANC01 kernel: [ 6758.373254] ses 4:0:17:0: Attached Enclosure device Mar 30 12:00:33 RANC01 kernel: [ 6758.373254] ses 4:0:17:0: Attached scsi generic sg0 type 13 Mar 30 12:00:33 RANC01 kernel: [ 6758.373254] ses 4:0:34:0: Attached Enclosure device Mar 30 12:00:33 RANC01 kernel: [ 6758.373254] ses 4:0:34:0: Attached scsi generic sg1 type 13 Mar 30 12:00:33 RANC01 kernel: [ 6758.373254] sd 4:2:0:0: [sda] Very big device. Trying to use READ CAPACITY(16). Mar 30 12:00:33 RANC01 kernel: [ 6758.373269] sd 4:2:0:0: [sda] 109366476800 512-byte hardware sectors (55995636 MB) Mar 30 12:00:33 RANC01 kernel: [ 6758.373286] sd 4:2:0:0: [sda] Write Protect is off Mar 30 12:00:33 RANC01 kernel: [ 6758.373286] sd 4:2:0:0: [sda] Mode Sense: 1f 00 10 08 Mar 30 12:00:33 RANC01 kernel: [ 6758.373314] sd 4:2:0:0: [sda] Write cache: disabled, read cache: enabled, supports DPO and FUA Mar 30 12:00:33 RANC01 kernel: [ 6758.373338] sd 4:2:0:0: [sda] Very big device. Trying to use READ CAPACITY(16). Mar 30 12:00:33 RANC01 kernel: [ 6758.373352] sd 4:2:0:0: [sda] 109366476800 512-byte hardware sectors (55995636 MB) Mar 30 12:00:33 RANC01 kernel: [ 6758.373365] sd 4:2:0:0: [sda] Write Protect is off Mar 30 12:00:33 RANC01 kernel: [ 6758.373365] sd 4:2:0:0: [sda] Mode Sense: 1f 00 10 08 Mar 30 12:00:33 RANC01 kernel: [ 6758.373393] sd 4:2:0:0: [sda] Write cache: disabled, read cache: enabled, supports DPO and FUA Mar 30 12:00:33 RANC01 kernel: [ 6758.373393] sda: Mar 30 12:00:33 RANC01 kernel: [ 6758.439120] sd 4:2:0:0: [sda] Attached SCSI disk Mar 30 12:00:33 RANC01 kernel: [ 6758.439120] sd 4:2:0:0: Attached scsi generic sg2 type 0 Mar 30 12:02:39 RANC01 kernel: [ 6904.599049] ERROR: (device sda1): dbAllocNext: Corrupt dmap page The JFS file system was ok when only one RAID 6 (about 24T) was included in logical volume. Now, I use XFS file system, no problem at all. regards, Feng Gao