ZFSOnLinux 0.6.2 released

[ryao]

Yeah, I realize they don't differentiate between 4KB and 8KB, which is somewhat problematic. On incompatibility, matching via pattern would seem to be a much more sensible idea, otherwise your list needs to be enormous for minor model variations, and it will take a seriously long time to catalogue them all. You'll also need to make changes every time a minor model rev is released, which going forward is likely to be every device released, until they stop lying, which could be a seriously long time. I understand the current method is more accurate, but it's also a maintenance nightmare, and specificity is pretty simply controlled by list order if you need to override an existing pattern for a special-case device. Also, since matching only happens very infrequently, the performance difference should have negligible impact.

Pattern matching could work well, but the current approach works and the time that it would take to implement pattern matching is better spent on higher priority issues.

I actually sort of wonder if it wouldn't have been a better idea to just go ashift=12 by default and potentially have a blacklist for true 512B devices.

Then all of the devices that should use ashift=13 would be given the wrong ashift by default. Unfortunately, there is no magic bullet for this issue.

[pdffs]

Aren't there several decades worth of 512B devices in use? Or do you mean SSDs only?

But how many of them are in use with a filesystem that's only been viable for the past couple of years?

[curaga]

I actually sort of wonder if it wouldn't have been a better idea to just go ashift=12 by default and potentially have a blacklist for true 512B devices.

Aren't there several decades worth of 512B devices in use? Or do you mean SSDs only?

[pdffs]

Thanks for the link. Unfortunately, the formats are not interchangeable. While entries can be copied from our list into FreeBSD, the reverse is not the case. It also does not make a distinction between drives with 4KB sectors and 8KB sectors.

On a semi-related note, FreeBSD currently uses that list solely to adjust stripe size, which ZFS does not use.

Yeah, I realize they don't differentiate between 4KB and 8KB, which is somewhat problematic. On incompatibility, matching via pattern would seem to be a much more sensible idea, otherwise your list needs to be enormous for minor model variations, and it will take a seriously long time to catalogue them all. You'll also need to make changes every time a minor model rev is released, which going forward is likely to be every device released, until they stop lying, which could be a seriously long time. I understand the current method is more accurate, but it's also a maintenance nightmare, and specificity is pretty simply controlled by list order if you need to override an existing pattern for a special-case device. Also, since matching only happens very infrequently, the performance difference should have negligible impact.

I actually sort of wonder if it wouldn't have been a better idea to just go ashift=12 by default and potentially have a blacklist for true 512B devices.

[ryao]

Just found this thread after Michael's most recent non-representative ZFS benchmark. And of course he managed to find an Intel SSD that's not in the blacklist. You might want to check the FreeBSD 4k quirks (ADA_Q_4K) list from ata_da.c to boost your list.

Thanks for the link. Unfortunately, the formats are not interchangeable. While entries can be copied from our list into FreeBSD, the reverse is not the case. It also does not make a distinction between drives with 4KB sectors and 8KB sectors.

On a semi-related note, FreeBSD currently uses that list solely to adjust stripe size, which ZFS does not use.

[pdffs]

Just found this thread after Michael's most recent non-representative ZFS benchmark. And of course he managed to find an Intel SSD that's not in the blacklist. You might want to check the FreeBSD 4k quirks (ADA_Q_4K) list from ata_da.c to boost your list.

[ryao]

on Gentoo, which is my main production system, I do (I even use the live-/9999-ebuilds )

For the moment, the 9999 ebuilds are effectively the same as the 0.6.2 ebuilds. The only difference is that the 0.6.2 SPL ebuild includes a patch for FreeBSD-style hostid detection that upstream has not adopted.

[kernelOfTruth]

you could always use the gentoo ebuilds :P

on Gentoo, which is my main production system, I do (I even use the live-/9999-ebuilds )

[energyman]

you could always use the gentoo ebuilds :P

[kernelOfTruth]

perfect timing, ryao !

Just was researching when the next stable release was going to get out to install on my dad's box

(last stable on the ubuntu ppa is/was already more than 20 weeks old and recent snapshot might be too much work in case there's some issues ... )