On Tuesday March 8, [EMAIL PROTECTED] wrote: > > berk walker wrote: > > Have you guys seen/tried mdadm 1.90? I am delightfully experiencing the > > I believe the mdadm based grow does not work for raid5, but only for > raid0 or raid1. raidreconf is actually capable of adding disks to raid5 > and re-laying out the stripes / moving parity blocks, etc
There are different dimensions for growing.... You can make the component devices bigger, or you can add component devices. You can increase storage or you can increase redundancy. If you replace all the devices in a raid1, raid5, or raid6 with large devices (presumably one at a time allowing for a reconstruct each time) then mdadm will allow you to "grow" the array to make use of the extra space. mdadm will also allow you to "grow" and raid1 array by adding extra devices. This only increases redundancy, not capacity. I code to allows you to "grow" a linear array by adding a drive to it. I'm not sure if I have submitted this code. I plan a raid4 version that organises the data in a linear rather than a striped fashion. It would be quite simple for mdadm to 'grow' this sort of array. All of these do not require moving data around, so they are easy. Growing a raid5 or raid6 by adding another drive is conceptually possible to do while the array is online, but I have not definite plans to do this (I would like to). Growing a raid5 into a raid6 would also be useful. These require moving lots of data around, and need to be able to cope with drive failure and system crash.... a fun project.. As has been said, raidreconf does at least some of this off-line. NeilBrown - To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
