Difference between revisions of "ZFS"

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(Created page with "So ZFS is all shiny and stuff. We'll be using it for disk based storage of backups for the following reasons: * All data (and metadata) can be validated with cryptographicall...")
 
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So, here's the first annoying thing I've come across. The ZFS tools go off and automatically mount filesystems in your just-created pool. '''And''' they go and make directories to mount those filesystems on. Quite annoying. What's wrong with putting entries in <code>/etc/fstab</code> and typing '''<code>mkdir /foo</code>'''? Instead '''<code>zfs pool create solarissucksballs ...</code>''' will create a <code>/solarissucksballs</code> directory on your machine and mount the new pool's filesystem there. I'm sure this behavior comes from Solaris, but I find it quite obnoxious.
 
So, here's the first annoying thing I've come across. The ZFS tools go off and automatically mount filesystems in your just-created pool. '''And''' they go and make directories to mount those filesystems on. Quite annoying. What's wrong with putting entries in <code>/etc/fstab</code> and typing '''<code>mkdir /foo</code>'''? Instead '''<code>zfs pool create solarissucksballs ...</code>''' will create a <code>/solarissucksballs</code> directory on your machine and mount the new pool's filesystem there. I'm sure this behavior comes from Solaris, but I find it quite obnoxious.
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== Some useful tidbits ==
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* <code>zfs set checksum=sha256 ''poolname''</code> # changes a filesystem's data integrity check algorithm from the default Fletcher4 to SHA256.
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* <code>zfs set dedup=sha256,verify ''poolname''</code> # enable dedupe, use SHA256 hashes as keys, but also do a bit-by-bit comparison before deciding two blocks are the same
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* <code>zfs set canmount=noauto ''poolname_OR_fsname''</code> # gets rid of the obnoxious /etc/fstab-less mounting behaviour at ZFS start time.

Revision as of 21:56, 5 March 2014

So ZFS is all shiny and stuff. We'll be using it for disk based storage of backups for the following reasons:

  • All data (and metadata) can be validated with cryptographically strong hashes
  • Data deduplication

Released versions of ZFSonLinux do not work on the kernels I'm running (3.12.x from backports.org), so I'm playing with zfs-fuse instead.

So, here's the first annoying thing I've come across. The ZFS tools go off and automatically mount filesystems in your just-created pool. And they go and make directories to mount those filesystems on. Quite annoying. What's wrong with putting entries in /etc/fstab and typing mkdir /foo? Instead zfs pool create solarissucksballs ... will create a /solarissucksballs directory on your machine and mount the new pool's filesystem there. I'm sure this behavior comes from Solaris, but I find it quite obnoxious.

Some useful tidbits

  • zfs set checksum=sha256 poolname # changes a filesystem's data integrity check algorithm from the default Fletcher4 to SHA256.
  • zfs set dedup=sha256,verify poolname # enable dedupe, use SHA256 hashes as keys, but also do a bit-by-bit comparison before deciding two blocks are the same
  • zfs set canmount=noauto poolname_OR_fsname # gets rid of the obnoxious /etc/fstab-less mounting behaviour at ZFS start time.