Re: question about creating a raid10

2019-01-18 Thread Chris Murphy
On Fri, Jan 18, 2019 at 12:02 AM Stefan K wrote: > > > Btrfs raid10 really should not be called raid10. It sets up the wrong > > user expectation entirely. It's more like raid0+1, except even that is > > deceptive because in theory a legit raid0+1 you can lose multiple > > drives on one side of th

Re: question about creating a raid10

2019-01-18 Thread Chris Murphy
On Thu, Jan 17, 2019 at 4:28 PM Tomasz Chmielewski wrote: > > > It is actually more like RAID-1E which is supported by some hardware > > RAID HBA. The difference is that RAID-1E is usually using strict > > sequential block placement algorithm and assumes disks of equal size, > > while btrfs raid10

Re: question about creating a raid10

2019-01-18 Thread Jukka Larja
Stefan K kirjoitti 18.1.2019 klo 9.02: WTF?! really, so with btrfs raid10 I can't lose more than one drive? that sucks, that an advantage of raid 10! and the crazy thing is, thats not documented, not in the manpage nor btrfs wiki and and thats is very important. thats unbelievable .. You sho

Re: question about creating a raid10

2019-01-17 Thread Stefan K
> Btrfs raid10 really should not be called raid10. It sets up the wrong > user expectation entirely. It's more like raid0+1, except even that is > deceptive because in theory a legit raid0+1 you can lose multiple > drives on one side of the mirror (but not both); but with Btrfs raid10 > you really

Re: question about creating a raid10

2019-01-17 Thread Tomasz Chmielewski
It is actually more like RAID-1E which is supported by some hardware RAID HBA. The difference is that RAID-1E is usually using strict sequential block placement algorithm and assumes disks of equal size, while btrfs raid10 is more flexible in selecting where next mirror pair is allocated. s/flex

Re: question about creating a raid10

2019-01-17 Thread Andrei Borzenkov
16.01.2019 21:15, Chris Murphy пишет: > > Btrfs raid10 really should not be called raid10. It sets up the wrong > user expectation entirely. It's more like raid0+1, It is actually more like RAID-1E which is supported by some hardware RAID HBA. The difference is that RAID-1E is usually using stric

Re: question about creating a raid10

2019-01-17 Thread Austin S. Hemmelgarn
On 2019-01-16 13:15, Chris Murphy wrote: On Wed, Jan 16, 2019 at 7:58 AM Stefan K wrote: :( that means when one jbod fail its there is no guarantee that it works fine? like in zfs? well that sucks Didn't anyone think to program it that way? The mirroring is a function of the block group,

RE: question about creating a raid10

2019-01-16 Thread Paul Jones
> -Original Message- > From: linux-btrfs-ow...@vger.kernel.org ow...@vger.kernel.org> On Behalf Of Chris Murphy > Sent: Thursday, 17 January 2019 5:15 AM > To: Stefan K > Cc: Linux Btrfs > Subject: Re: question about creating a raid10 > > On Wed, Jan 16, 2019

Re: question about creating a raid10

2019-01-16 Thread Chris Murphy
On Wed, Jan 16, 2019 at 7:58 AM Stefan K wrote: > > :( > that means when one jbod fail its there is no guarantee that it works fine? > like in zfs? well that sucks > Didn't anyone think to program it that way? The mirroring is a function of the block group, not the block device. And yes that's

Re: question about creating a raid10

2019-01-16 Thread Stefan K
:( that means when one jbod fail its there is no guarantee that it works fine? like in zfs? well that sucks Didn't anyone think to program it that way? On Wednesday, January 16, 2019 2:42:08 PM CET Hugo Mills wrote: > On Wed, Jan 16, 2019 at 03:36:25PM +0100, Stefan K wrote: > > Hello, > > > >

Re: question about creating a raid10

2019-01-16 Thread Hugo Mills
On Wed, Jan 16, 2019 at 03:36:25PM +0100, Stefan K wrote: > Hello, > > if I create a raid10 it looks like that: > mkfs.btrfs -m raid10 -d raid10 /dev/sdb /dev/sdc /dev/sdd /dev/sde > > but if I've different jbods and I want that every mirror of a raid10 is on a > different jbod how can I archive