* SATA/SAS mixed pool @ 2018-12-13 3:31 Nathan Dehnel 2018-12-13 4:07 ` Zia Nayamuth 2018-12-13 7:29 ` Adam Borowski 0 siblings, 2 replies; 7+ messages in thread From: Nathan Dehnel @ 2018-12-13 3:31 UTC (permalink / raw) To: linux-btrfs Is it possible/safe to replace a SATA drive in a btrfs RAID10 pool with an SAS drive? ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: SATA/SAS mixed pool 2018-12-13 3:31 SATA/SAS mixed pool Nathan Dehnel @ 2018-12-13 4:07 ` Zia Nayamuth 2018-12-13 7:29 ` Adam Borowski 1 sibling, 0 replies; 7+ messages in thread From: Zia Nayamuth @ 2018-12-13 4:07 UTC (permalink / raw) To: Nathan Dehnel; +Cc: linux-btrfs I've done it with ZFS and hardraid controllers. I see no reason why btrfs should care. On 2018-12-13 07:31, Nathan Dehnel wrote: > Is it possible/safe to replace a SATA drive in a btrfs RAID10 pool > with an SAS drive? ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: SATA/SAS mixed pool 2018-12-13 3:31 SATA/SAS mixed pool Nathan Dehnel 2018-12-13 4:07 ` Zia Nayamuth @ 2018-12-13 7:29 ` Adam Borowski 2018-12-13 10:39 ` Remi Gauvin 2018-12-14 5:14 ` Duncan 1 sibling, 2 replies; 7+ messages in thread From: Adam Borowski @ 2018-12-13 7:29 UTC (permalink / raw) To: Nathan Dehnel; +Cc: linux-btrfs On Wed, Dec 12, 2018 at 09:31:02PM -0600, Nathan Dehnel wrote: > Is it possible/safe to replace a SATA drive in a btrfs RAID10 pool > with an SAS drive? For btrfs, a block device is a block device, it's not "racist". You can freely mix and/or replace. If you want to, say, extend a SD card with NBD to remote spinning rust, it works well -- tested :p Meow! -- ⢀⣴⠾⠻⢶⣦⠀ ⣾⠁⢠⠒⠀⣿⡁ Ivan was a worldly man: born in St. Petersburg, raised in ⢿⡄⠘⠷⠚⠋⠀ Petrograd, lived most of his life in Leningrad, then returned ⠈⠳⣄⠀⠀⠀⠀ to the city of his birth to die. ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: SATA/SAS mixed pool 2018-12-13 7:29 ` Adam Borowski @ 2018-12-13 10:39 ` Remi Gauvin 2018-12-13 12:48 ` Austin S. Hemmelgarn 2018-12-14 5:14 ` Duncan 1 sibling, 1 reply; 7+ messages in thread From: Remi Gauvin @ 2018-12-13 10:39 UTC (permalink / raw) To: Adam Borowski, Nathan Dehnel; +Cc: linux-btrfs [-- Attachment #1.1.1: Type: text/plain, Size: 718 bytes --] On 2018-12-13 02:29 AM, Adam Borowski wrote: > > For btrfs, a block device is a block device, it's not "racist". > You can freely mix and/or replace. If you want to, say, extend a SD > card with NBD to remote spinning rust, it works well -- tested :p > The possibility ff NBD certainly intrigues me, but I would be concerned about the write barriers,, (needed to make sure cached writes are committed to spinning rust in the correct order, so as to avoid corruption in the case of interruption. Assuming the underlaying block device on the remote device has a working implementation, (as we know, not always a safe assumption...) does NBD properly pass along the barriers commands/support? [-- Attachment #1.1.2: remi.vcf --] [-- Type: text/x-vcard, Size: 203 bytes --] begin:vcard fn:Remi Gauvin n:Gauvin;Remi org:Georgian Infotech adr:;;3-51 Sykes St. N.;Meaford;ON;N4L 1X3;Canada email;internet:remi@georgianit.com tel;work:226-256-1545 version:2.1 end:vcard [-- Attachment #2: OpenPGP digital signature --] [-- Type: application/pgp-signature, Size: 473 bytes --] ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: SATA/SAS mixed pool 2018-12-13 10:39 ` Remi Gauvin @ 2018-12-13 12:48 ` Austin S. Hemmelgarn 0 siblings, 0 replies; 7+ messages in thread From: Austin S. Hemmelgarn @ 2018-12-13 12:48 UTC (permalink / raw) To: Remi Gauvin, Adam Borowski, Nathan Dehnel; +Cc: linux-btrfs On 2018-12-13 05:39, Remi Gauvin wrote: > On 2018-12-13 02:29 AM, Adam Borowski wrote: > >> >> For btrfs, a block device is a block device, it's not "racist". >> You can freely mix and/or replace. If you want to, say, extend a SD >> card with NBD to remote spinning rust, it works well -- tested :p >> > > The possibility ff NBD certainly intrigues me, but I would be concerned > about the write barriers,, (needed to make sure cached writes are > committed to spinning rust in the correct order, so as to avoid > corruption in the case of interruption. > > Assuming the underlaying block device on the remote device has a working > implementation, (as we know, not always a safe assumption...) does NBD > properly pass along the barriers commands/support? I don't think there's any auto-detection, but newer versions of the NBD server software provide two options in the export configuration, `flush`, and `fua`, which will let you enable support for those two commands, though they only get used if the client supports them. Unless I'm mistaken, they both need support from the block device being exported if it's actually a block device, though they do not if it's a regular file (`flush` translates to `fdatasync()` or `fsync()`, while `fua` translates to `sync_file_range()`). ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: SATA/SAS mixed pool 2018-12-13 7:29 ` Adam Borowski 2018-12-13 10:39 ` Remi Gauvin @ 2018-12-14 5:14 ` Duncan 2018-12-14 15:26 ` Adam Borowski 1 sibling, 1 reply; 7+ messages in thread From: Duncan @ 2018-12-14 5:14 UTC (permalink / raw) To: linux-btrfs Adam Borowski posted on Thu, 13 Dec 2018 08:29:05 +0100 as excerpted: > On Wed, Dec 12, 2018 at 09:31:02PM -0600, Nathan Dehnel wrote: >> Is it possible/safe to replace a SATA drive in a btrfs RAID10 pool with >> an SAS drive? > > For btrfs, a block device is a block device, it's not "racist". > You can freely mix and/or replace. If you want to, say, extend a SD > card with NBD to remote spinning rust, it works well -- tested :p FWIW (mostly for other readers not so much this particular case) the known exception/caveat to that is USB block devices, which do tend to have problems, tho some hardware is fine. -- Duncan - List replies preferred. No HTML msgs. "Every nonfree program has a lord, a master -- and if you use the program, he is your master." Richard Stallman ^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: SATA/SAS mixed pool 2018-12-14 5:14 ` Duncan @ 2018-12-14 15:26 ` Adam Borowski 0 siblings, 0 replies; 7+ messages in thread From: Adam Borowski @ 2018-12-14 15:26 UTC (permalink / raw) To: linux-btrfs On Fri, Dec 14, 2018 at 05:14:37AM +0000, Duncan wrote: > Adam Borowski posted on Thu, 13 Dec 2018 08:29:05 +0100 as excerpted: > > On Wed, Dec 12, 2018 at 09:31:02PM -0600, Nathan Dehnel wrote: > >> Is it possible/safe to replace a SATA drive in a btrfs RAID10 pool with > >> an SAS drive? > > > > For btrfs, a block device is a block device, it's not "racist". > > You can freely mix and/or replace. If you want to, say, extend a SD > > card with NBD to remote spinning rust, it works well -- tested :p > > FWIW (mostly for other readers not so much this particular case) the > known exception/caveat to that is USB block devices, which do tend to > have problems, tho some hardware is fine. Yeah, but the problem doesn't come from btrfs not supporting or ill supporting USB, just from the devices themselves being flaky. If they supported the spec correctly, all would be ok. An example might be NBD from one of my machines that has an incredibly bad network driver -- it drops packets whenever there's even a bit of memory pressure. That's ok on RX (no different from packet being dropped on the wire, the sender will retransmit) but unacceptable on TX -- it should have slept instead; NBD (reasonably) can't handle this and destroys the block device. Yet btrfs can handle such an unexpected but clean disconnect just fine -- not even a reboot is needed, I need to unmount, restart NBD then remount. From the filesystem's point of view this is exactly equivalent to a power loss -- that the in-memory copy tried to do some writes afterwards doesn't matter. So it's not just whether the device fails, it's about _how_ it fails. Meow! -- ⢀⣴⠾⠻⢶⣦⠀ ⣾⠁⢠⠒⠀⣿⡁ Ivan was a worldly man: born in St. Petersburg, raised in ⢿⡄⠘⠷⠚⠋⠀ Petrograd, lived most of his life in Leningrad, then returned ⠈⠳⣄⠀⠀⠀⠀ to the city of his birth to die. ^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2018-12-14 15:26 UTC | newest] Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2018-12-13 3:31 SATA/SAS mixed pool Nathan Dehnel 2018-12-13 4:07 ` Zia Nayamuth 2018-12-13 7:29 ` Adam Borowski 2018-12-13 10:39 ` Remi Gauvin 2018-12-13 12:48 ` Austin S. Hemmelgarn 2018-12-14 5:14 ` Duncan 2018-12-14 15:26 ` Adam Borowski
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