On Thu, December 4, 2008 11:26 pm, Chris Webb wrote: > The amount of space reserved in each component for an internal bitmap > depends on the size of the component. If I have (say) a raid5 arrray of > size > 50GB that used to be a raid5 array of size 1GB, and I fail one of the > slots > and add in a new replacement, the new slot needs to be bigger than all the > existing ones because a larger space is reserved by mdadm for the internal > bitmap. > > 3# mdadm --version && uname -sv > mdadm - v2.6.7 - 6th June 2008 Fixed in v2.6.8, commit 2a528478c75b6659188fc2ce0d9543124992fe6c NeilBrown > Linux 2.6.27.7 #2 SMP Wed Dec 3 12:00:03 GMT 2008 > > 3# mdadm --fail /dev/md127 /dev/mapper/slot.51000.1 > mdadm: set /dev/mapper/slot.51000.1 faulty in /dev/md127 > 3# mdadm --remove /dev/md127 /dev/mapper/slot.51000.1 > mdadm: hot removed /dev/mapper/slot.51000.1 > > 3# # wipe superblock so this is a new slot rather than a re-add... > 3# dd if=/dev/zero of=/dev/mapper/slot.51000.1 bs=1M count=1 > 1+0 records in > 1+0 records out > 3# mdadm --add /dev/md127 /dev/mapper/slot.51000.1 > mdadm: /dev/mapper/slot.51000.1 not large enough to join array > > 3# mdadm --examine /dev/mapper/slot.51000.0 > /dev/mapper/slot.51000.0: > Magic : a92b4efc > Version : 1.1 > Feature Map : 0x0 > Array UUID : 61a6b9ac:4b38148f:c0c0837e:1c34783f > Name : 3:shelf.51000 > Creation Time : Thu Dec 4 11:21:49 2008 > Raid Level : raid1 > Raid Devices : 2 > > Avail Dev Size : 104857584 (50.00 GiB 53.69 GB) > Array Size : 104857584 (50.00 GiB 53.69 GB) > Data Offset : 16 sectors > Super Offset : 0 sectors > State : active > Device UUID : f8c6dcec:add24452:267858ec:617382cd > > Update Time : Thu Dec 4 12:07:22 2008 > Checksum : 1e90683 - correct > Events : 19 > > > Array Slot : 0 (0, failed) > Array State : U_ 1 failed > > > Is there any way either to persuade mdadm to take the bitmap size for from > the > existing components, or ideally to override the bitmap size when creating > arrays and adding components so I can just choose a constant size for all > our > automatically generated arrays, given that the arrays will vary in size > over > their lifetimes? > > Best wishes, > > Chris. > -- > To unsubscribe from this list: send the line "unsubscribe linux-raid" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
