I am going to be building a new file server in a couple weeks and am deciding on how to structure it. Previously, I ran RAID5 through mdadm and XFS on Debian, but I had a silently bad drive that corrupted data without dropping from the array. I suspected this was happening, and changed over to ZFS on FreeNAS and the monthly scrub told me exactly what was going on. That sold me on the idea of data checksums, but I'd rather stay in linux than BSD, and I previously made use of online capacity expansion as needed, which ZFS doesn't support.
Enter btrfs. Unfortunately, it's newer than ZFS and isn't as robust, but it does support online capacity expansion, and the on disk format is expect to be stable. It has data checksums and COW, which are the primary things I'm after. RAID10 seems pretty stable, but RAID56 isn't. So I'm looking for a suggestion. My end goal is RAID6 and expand it a drive at a time as needed. For right now, I can either: 1) Run RAID6, but be aware of its limitations. I can manually remove and add drives in separate steps if needed. Keep the server on a UPS to limit unexpected shutdowns and any corruption there. The whole array can't be scrubbed, but if there is a chechsum problem when reading individual data, will that still be corrected and/or logged? This will be a temporary situation, as over time, more features will be built out, and the existing file system will be better supported. 2) Run RAID10, and convert the file system to RAID6 later once it is stable. Since RAID10 is far more stable and feature complete than RAID56 right now, all features will work okay, I'm just buying more drives/running at lower capacity for the moment. If I have to grow the array, I'd have to buy two drives. In the future, once RAID6 is better supported, I can convert in-place to RAID6. What do you think? Thanks, Andrew -- 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
