Vic/zfs faq

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ZFS FAQ

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How do I create a simple stripe zpool?

  • zpool create Simple:Stripe c1t500A09858290C139d198 c1t500A09858290C139d197 \
  • c1t500A09858290C139d196 c1t500A09858290C139d195 c1t500A09858290C139d194 \
  • c1t500A09858290C139d193 c1t500A09858290C139d192 
[root@shsun07--->]df -h /Simple:Stripe
Filesystem             size   used  avail capacity  Mounted on
Simple:Stripe           14G    24K    14G     1%    /Simple:Stripe
  • Discussion - Best practice is to always create zpools with whole disks. Zpools may be created with slices or even files within a UFS filesystem however this would greatly limit ZFS functionality. For example it zpools are sharing disks with UFS then the zpool can not be exported and imported on another host.
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How do I grow a zpool?

  • zpool add Simple:Stripe c1t500A09858290C139d174 
[root@shsun07--->]df -h /Simple:Stripe
Filesystem             size   used  avail capacity  Mounted on
Simple:Stripe           16G    24K    16G     1%    /Simple:Stripe
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How can I check the health of a zpool?

[root@shsun07--->]zpool status Simple:Stripe
  pool: Simple:Stripe
 state: ONLINE
 scrub: none requested
config:

        NAME                       STATE     READ WRITE CKSUM
        Simple:Stripe              ONLINE       0     0     0
          c1t500A09858290C139d198  ONLINE       0     0     0
          c1t500A09858290C139d197  ONLINE       0     0     0
          c1t500A09858290C139d196  ONLINE       0     0     0
          c1t500A09858290C139d195  ONLINE       0     0     0
          c1t500A09858290C139d194  ONLINE       0     0     0
          c1t500A09858290C139d193  ONLINE       0     0     0
          c1t500A09858290C139d192  ONLINE       0     0     0
          c1t500A09858290C139d174  ONLINE       0     0     0

errors: No known data errors
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Can I measure disk performance within a zpool?

[root@shsun07--->]zpool iostat -v Simple:Stripe   
                              capacity     operations    bandwidth
pool                        used  avail   read  write   read  write
-------------------------  -----  -----  -----  -----  -----  -----
Simple:Stripe               189K  15.9G      0      1      0  18.5K
  c1t500A09858290C139d198    90K  1.98G      0      0      0  2.46K
  c1t500A09858290C139d197    29K  1.98G      0      0      0  2.28K
  c1t500A09858290C139d196  2.50K  1.98G      0      0      0  2.18K
  c1t500A09858290C139d195      0  1.98G      0      0      0  2.17K
  c1t500A09858290C139d194      0  1.98G      0      0      0  2.17K
  c1t500A09858290C139d193      0  1.98G      0      0      0  2.17K
  c1t500A09858290C139d192  67.5K  1.98G      0      0      0  2.40K
  c1t500A09858290C139d174      0  1.98G      0      0      0  3.81K
-------------------------  -----  -----  -----  -----  -----  -----
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How do I see previously configured zpools?

[root@shsun07--->]zpool list
NAME                    SIZE    USED   AVAIL    CAP  HEALTH     ALTROOT
Simple:Stripe          15.9G    189K   15.9G     0%  ONLINE     -
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Can zpools be exported and imported?

  • zpool export Simple:Stripe
  • zpool import Simple:Stripe
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How do I see zpools available to be imported?

  • zpool import
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How do I create zfs filesystems

[root@shsun07--->]zfs create Simple:Stripe/home
[root@shsun07--->]df -h Simple:Stripe/home
Filesystem             size   used  avail capacity  Mounted on
Simple:Stripe           16G    26K    16G     1%    /Simple:Stripe
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How can I list existing zfs filesystems

[root@shsun07--->]zfs list
NAME                   USED  AVAIL  REFER  MOUNTPOINT
Simple:Stripe          114K  15.6G  26.5K  /Simple:Stripe
Simple:Stripe/home    24.5K  15.6G  24.5K  /Simple:Stripe/home
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Can I change the mountpoint for a zfs filesystem, /Simple:Stripe/home looks stupid

[root@shsun07--->]zfs set mountpoint=/zhome Simple:Stripe/home
[root@shsun07--->]zfs list
NAME                   USED  AVAIL  REFER  MOUNTPOINT
Simple:Stripe          120K  15.6G  26.5K  /Simple:Stripe
Simple:Stripe/home    24.5K  15.6G  24.5K  /zhome
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How do I share zfs filesystems

[root@shsun07--->]zfs set sharenfs=on Simple:Stripe/home
[root@shsun07--->]showmount -e
export list for shsun07:
/zhome (everyone)
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What is a zvol

  • A zvol is a virtual disk device with a zfs filesystem as the backing store.
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How do I create a zvol?

[root@shsun07--->]zfs create -V 5g Simple:Stripe/vdisk
[root@shsun07--->]file /dev/zvol/rdsk/Simple\:Stripe/vdisk 
/dev/zvol/rdsk/Simple:Stripe/vdisk:     character special (256/1)
  • The zvol named vdisk can now be newfs'd and mounted traditionally or used as raw space.
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How do I create a snapshot?


[root@shsun15--->]zfs set snapdir=visible oracle_db/training

[root@shsun15--->]zfs snapshot oracle_db/training@Friday315pm


[root@shsun15--->]zfs list
NAME                   USED  AVAIL  REFER  MOUNTPOINT
SimpleStripe            79K  9.77G  24.5K  /SimpleStripe
oracle_db             56.8M  13.6G  25.5K  /oracle_db
oracle_db/training    56.7M  13.6G  56.7M  /oracle_db/training
oracle_db/training@Friday315pm      0      -  56.7M  -
oracle_logs            175K  9.77G  28.5K  /oracle_logs
oracle_logs/log_1     24.5K  9.77G  24.5K  /oracle_logs/log_1
oracle_logs/log_2     24.5K  9.77G  24.5K  /oracle_logs/log_2
oracle_logs/log_3     24.5K  9.77G  24.5K  /oracle_logs/log_3

[root@shsun15--->]ls -l /oracle_db/training/release
-r--r--r--   1 root     sys          242 Nov 14 18:02 /oracle_db/training/release

[root@shsun15--->]ls -l /oracle_db/training/.zfs/snapshot/Friday315pm/release
-r--r--r--   1 root     sys          242 Nov 14 18:02 /oracle_db/training/.zfs/snapshot/Friday315pm/release
  • Note - The default snapdir property is hidden. To make the .zfs directory visible to users change this property to "visible".
Retrieved from "http://www.vicengle.org/wiki/Vic/zfs_faq"
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