On 30 August 2016 at 11:09, Carlos E. R.
On 2016-08-30 04:25, Jeff Mahoney wrote:
On 8/29/16 5:42 PM, Lindsay Mathieson wrote:
Given the debacle over RAID 5/6 and the ongoing issues with stability, and supposedly a very messy codebase, is btrfs still a wise default for installs?
Those are three separate issues. The first is, from our (SUSE) perspective, isn't an issue. We don't support RAID 5/6, full stop.
I assume you mean btrfs with RAID 5/6. Software raid with any other filesystem is Ok, right?
Ok is a matter of perspective. All RAID 5/6 implementations, including hardware ones, are at risk of a 'write hole', when something interupts the write. When this happens, the parity information doesn't match the rest of the data for the stripe. For hardware raid this is typically only during a power outage. Software RAID has an increased chance of this happening, due to increased opportunities for something to interupt that write, such as a kernel crash. Hardware RAID arrays mitigate this risk by using either non-volitile caches or battery backups to allow the writes to complete even in the event of a power outage. Software RAID has no such mitigations. So, RAID 5/6 always comes with an element of risk. A high-end hardware controller with NV cache and theoretically 'perfect' firmware has little risk. A well maintained hardware controller with a sysadmin regularly taking care that the battery is working has a small risk. and then it increases from there. And the btrfs RAID 5/6 implementation is probably the least safe of all the software RAID options available on openSUSE (and is therefore not available on SLE). But I personally wouldn't recommend any software RAID 5/6 of any type on any openSUSE filesystem for anyone who want to ensure their data is consistant and stays that way. -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org