Re: BTRFS RAM requirements, RAID 6 stability/write holes and expansion questions

On 2016-02-11 09:14, Goffredo Baroncelli wrote: On 2016-02-10 20:59, Austin S. Hemmelgarn wrote: [...] Again, a torn write to the metadata referencing the block (stripe in this case I believe) will result in loosing anything written by the update to the stripe. I think that the order matters:

Re: BTRFS RAM requirements, RAID 6 stability/write holes and expansion questions

On 2016-02-10 20:59, Austin S. Hemmelgarn wrote: [...] > Again, a torn write to the metadata referencing the block (stripe in > this case I believe) will result in loosing anything written by the > update to the stripe. I think that the order matters: first the data block are written (in a new

Re: BTRFS RAM requirements, RAID 6 stability/write holes and expansion questions

On Thu, Feb 11, 2016 at 7:58 AM, Austin S. Hemmelgarn wrote: > On 2016-02-11 09:14, Goffredo Baroncelli wrote: >> >> On 2016-02-10 20:59, Austin S. Hemmelgarn wrote: >> [...] >>> >>> Again, a torn write to the metadata referencing the block (stripe in >>> this case I

Re: BTRFS RAM requirements, RAID 6 stability/write holes and expansion questions

On 2016-02-09 15:39, Chris Murphy wrote: On Fri, Feb 5, 2016 at 12:36 PM, Mackenzie Meyer wrote: RAID 6 write holes? I don't even understand the nature of the write hole on Btrfs. If modification is still always COW, then either an fs block, a strip, or whole stripe

Re: BTRFS RAM requirements, RAID 6 stability/write holes and expansion questions

On Wed, Feb 10, 2016 at 6:57 AM, Austin S. Hemmelgarn wrote: > It's an issue of torn writes in this case, not of atomicity of BTRFS. Disks > can't atomically write more than sector size chunks, which means that almost > all BTRFS filesystems are doing writes that disks

Re: BTRFS RAM requirements, RAID 6 stability/write holes and expansion questions

On 2016-02-10 14:06, Chris Murphy wrote: On Wed, Feb 10, 2016 at 6:57 AM, Austin S. Hemmelgarn wrote: It's an issue of torn writes in this case, not of atomicity of BTRFS. Disks can't atomically write more than sector size chunks, which means that almost all BTRFS

Re: BTRFS RAM requirements, RAID 6 stability/write holes and expansion questions

On 05/02/16 20:36, Mackenzie Meyer wrote: RAID 6 stability? I'll say more: currently, btrfs is in a state of flux where if you don't have a very recent kernel that's the first recommendation you're going to receive in case of problems. This means going out of stable packages in most distros.

Re: BTRFS RAM requirements, RAID 6 stability/write holes and expansion questions

On Fri, Feb 5, 2016 at 12:36 PM, Mackenzie Meyer wrote: > > RAID 6 write holes? I don't even understand the nature of the write hole on Btrfs. If modification is still always COW, then either an fs block, a strip, or whole stripe write happens, I'm not sure where the

Re: BTRFS RAM requirements, RAID 6 stability/write holes and expansion questions

On 05/02/16 20:36, Mackenzie Meyer wrote: Hello, I've tried checking around on google but can't find information regarding the RAM requirements of BTRFS and most of the topics on stability seem quite old. To keep my answer short: every time I've tried (offline) deduplication or raid5 pools

Re: BTRFS RAM requirements, RAID 6 stability/write holes and expansion questions

Mackenzie Meyer posted on Fri, 05 Feb 2016 14:36:33 -0500 as excerpted: > Hello, > > I've tried checking around on google but can't find information > regarding the RAM requirements of BTRFS and most of the topics on > stability seem quite old. > > So first would be memory requirements, my goal

BTRFS RAM requirements, RAID 6 stability/write holes and expansion questions

Hello, I've tried checking around on google but can't find information regarding the RAM requirements of BTRFS and most of the topics on stability seem quite old. So first would be memory requirements, my goal is to use deduplication and compression. Approximately how many GB of RAM per TB of