2008/12/29 Chris Samuel <ch...@csamuel.org>: > On Sat, 27 Dec 2008 5:45:42 pm Chris Samuel wrote: > >> I'll add two questions that're not answered by the Wiki too.. :-) > > Looking at the source implies to me: > >> 1) If you add a second disk to an existing btrfs filesystem, can you get it >> to set it up as a RAID-1 arrangement rather than just rebalancing the >> metadata and then striping ? > > No, you can't, the data stripe numbers seem to be set at mkfs time. > > The rebalancing code does appear (from a naive read of the code) to be able to > rebalance over stripes, but I have no idea if the disk format currently > supports changing that on the fly. >
The rebalancing moves data/metadata to newly created chunks. If there are two devices, the new chunks will be set up as RAID-1 by default. >> 2) With the concerns that people have about SSD reliability (hi Val :-) !) >> would it make sense to set up two equal sized partitions on the SSD and use >> RAID-1 across them, or can you tell btrfs to keep multiple copies of the >> data, a la ZFS ? > > Again it would appear that you need to have two partitions and that btrfs > cannot (at present) keep multiple data stripes on the same partition. > Yes. I think this is due to performance reason. Changing the code to support data duplication in single spindle configuration is easy. Regards Yan Zheng -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
