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mahrens (Matthew Ahrens)
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User Since
Jul 24 2014, 3:11 AM (229 w, 2 d)

Recent Activity

Jun 11 2018

mahrens requested changes to D15748: Support destroy of multiple bookmarks on a single dataset..
Jun 11 2018, 5:49 PM · ZFS

Apr 18 2018

mahrens added reviewers for D15124: raidz expansion PRE-ALPHA CODE: mckusick, emaste, allanjude.
Apr 18 2018, 12:09 AM
mahrens created D15124: raidz expansion PRE-ALPHA CODE.
Apr 18 2018, 12:07 AM

Apr 17 2018

mahrens accepted D15076: Make `iostat -xC` print CPU information on its own line.

Thanks!

Apr 17 2018, 4:18 PM

Dec 5 2017

mahrens added a comment to D11124: ZSTD compression for ZFS.

So you only have one new compression value in the BP? Have you looked at how this interacts with L2ARC when compressed ARC is disabled? See arc_cksum_is_equal(), I don't think this will work right, because you won't be able to reproduce the on-disk compressed data without knowing the compression level.

Dec 5 2017, 4:56 PM

Sep 20 2017

mahrens added a comment to D12396: Default ABD chunk size.

@seanc OpenZFS/illumos has been at 4K chunk size since ABD was introduced. I'm not aware of any discussion around changing that.

Sep 20 2017, 3:55 PM · ZFS

Sep 17 2017

mahrens added a comment to D12396: Default ABD chunk size.

FYI - we use 1K ABD chunks at Delphix (on illumos), and we've found that up to 40% of memory can end up being wasted because of memory fragmentation. At least on illumos, the 1K ABD kmem cache will use slab size 4K (one page), so there are 4 chunks per slab. After eviction, we may have many partially-full slabs, which wastes the free chunks. We are considering implementing a kmem_move callback which would allow the free chunks to be consolidated, reducing the potential for memory waste. But it isn't done yet.

Sep 17 2017, 2:58 AM · ZFS

Jul 19 2016

mahrens added a member for ZFS: mahrens.
Jul 19 2016, 8:24 PM
mahrens added inline comments to D6533: zfs: step #1 of bringing zpl to full obedience of vfs.
Jul 19 2016, 8:24 PM

Jun 13 2016

mahrens committed rS301876: Add myself (mahrens) to calendar.freebsd.
Add myself (mahrens) to calendar.freebsd
Jun 13 2016, 11:36 PM

Dec 23 2015

mahrens accepted D4691: zdb: report an error if initialisation fails.
Dec 23 2015, 12:02 AM
mahrens added a comment to D4691: zdb: report an error if initialisation fails.

looks good. Happy to have this upstream too.

Dec 23 2015, 12:02 AM

Nov 10 2015

mahrens added a comment to D3478: GCC Warning - unused-but-set-variable.

You can use the instructions here: https://github.com/openzfs/openzfs to submit a pull request and get regression tests. Then solicit code reviews to developer@lists.illumos.org.

Nov 10 2015, 4:24 PM

Nov 2 2015

mahrens added a comment to D4074: Make 'zfs release' accept a filesystem instead of only snapshots.

What is the use case for this? AFAIK it isn't possible to create all those holds with one zfs command (there's just "zfs holds -r <snapshot>" which creates a hold on one snapshot per filesystem.

Nov 2 2015, 10:48 PM

Oct 25 2015

mahrens accepted D3994: Extend 'zfs holds -r' to accept a dataset, instead of only a snapshot as input.
Oct 25 2015, 7:51 PM
mahrens added inline comments to D3994: Extend 'zfs holds -r' to accept a dataset, instead of only a snapshot as input.
Oct 25 2015, 4:58 AM

Oct 24 2015

mahrens added a comment to D3994: Extend 'zfs holds -r' to accept a dataset, instead of only a snapshot as input.

This is a good start, but you also need to update the manpage and help message (see get_usage()).

Oct 24 2015, 5:09 AM

Jun 20 2015

mahrens accepted D2865: zfs_mount(MS_REMOUNT): protect zfs_(un)register_callbacks calls.
Jun 20 2015, 3:30 PM

Jun 18 2015

mahrens accepted D2839: illums compat: use flsl/flsll for highbit/highbit64.

Looks fine to me. FWIW, illumos appears to have flsll() in userland but not kernel. It's implemented similarly to highbit().

Jun 18 2015, 7:53 PM

Jun 11 2015

mahrens accepted D2722: Fix some clang warnings..
Jun 11 2015, 3:03 PM

Jun 10 2015

mahrens added inline comments to D2722: Fix some clang warnings..
Jun 10 2015, 10:02 PM

Mar 15 2015

mahrens retitled D2068: add mahrens as committer from to add mahrens as committer.
Mar 15 2015, 1:44 AM

Aug 7 2014

mahrens accepted D472: Quisece one printf warnings.
Aug 7 2014, 10:16 PM
mahrens added a comment to D472: Quisece one printf warnings.

looks good to me.

Aug 7 2014, 10:15 PM

Jul 24 2014

mahrens added inline comments to D472: Quisece one printf warnings.
Jul 24 2014, 3:15 AM