ZFS vs. Linux Raid vs. Linux LVM vs. Linux LVM + Raid

Source By James Dickensuadmin.blogspot.comSubmit changes, enhancements, or comments to jamesd DOT wi AT gmail DOT com

	ZFS	Linux  Raid	Linux  LVM	Linux  LVM + Raid
Raid Types
Single drive	Yes	N/A	Yes	Yes
Raid-0	Yes	Yes	Yes	Yes
Raid-1	Yes	Yes	No	Yes
Raid-1+0	Yes	No	No	Yes
Raid-5	Noi	Yes	No	Yes
Raid-5+0	No	No	No	Yes
Raidzii	Yes	No	No	No
Raidz+0	Yes	No	No	No
Administrative tasks
Non-endian  specific	Yes	No	No	No
Import/Export Pools/Dataset	Yes	Not automated	Not  automated	Not automated
iostat built to  gives details  of IO utilization	Yes	No	No	No
Snapshots
Snapshots/online?	Yes/online	No	Yes/offline only	Yes/offline only
Requires separate slice	No	N/A	Yes	Yes
Uses more  than 1%  of data space  to create	No	N/A	Yes	Yes
Rollbackiii	Yes	No	No	No
Clonesiv	Yes	No	No	No
Growing File Systems Online
Convert from  single drive  to raid1	Yes	Yes	No	Yes
Convert from Raid1 to Raid 1+0	Yes	N/A	N/A	Yes
Convert from Raid1 to Raid5/z	No/may be  possible  in the future	Yes/offline	N/A	Yes/offline
Grow a raid0	Yes/Yes	Yes/Yes	Yes/Yes	Yes/yes
Grow a raid5/z	No/may be  possible in the future	Yes/offline	Yes/offline	Yes/offline
Convert from Raid5/z to Raid5/z+0	Yes/Yes	No	No	Yes/yes
Coping with difficulties
Handles whole  disk failure	Yes	Yes	Yes	Yes
Checksum's  all data	Yes	No	No	No
Copes with  disk corruption	Yes	Nov	Nov	Nov
Special Attributes
Optional On Disk Compression	Yes built in.	No/requires  another layer  of software	No/requires  another layer  of software	No/requires  another  layer of software
Multiple volume/filesystems per device/pool	Yes	No	Yes	Yes
Integrated NFS support	Yes	No	No	No
Recursively  apply File  system attributes	Yes	No	No	No
Built-in backup/restore support	Yes	No	No	No
Space Shared between all filesystems  in the  pool/dataset	Yes	One filesystem  per device	You preallocate  space per  filesystem	You preallocate space  per filesystem
Integrated quotas	Per filesystem	Not Integrated  but more  flexible	Not Integrated but more  flexible	Not Integrated  but more  flexible
Integrated Reservations	Yes	No	No	No

Sources

1. Solaris Express man pages, zpool(1M), zfs(1M)
2. Software RAID http://www.tldp.org/HOWTO/

Footnotes

i   ZFS doesn't support raid 5 but does support raid-z that has better features and less limitations

ii  RaidZ - A variation on RAID-5 which allows for better distribution of parity and eliminates the "RAID-5 write hole" (in which data and parity become inconsistent after a power loss). Data and parity is striped across all disks within a raidz group. A raidz group with N disks of size X can hold approximately (N-1)*Xbytes and can withstand one device failing before data integrity is compromised. The minimum number of devices in a raidz group is 2; the recommended number is between 3 and 9.

iii  Rollback the given dataset to a previous snapshot. When a dataset is rolled back, all data that has changed since the snapshot is discarded, and the dataset reverts to the state at the time of the snapshot.

iv  A clone is a writable volume or file system whose initialcontents are the same as another dataset. As with snapshots, creating a clone is nearly instantaneous, and initially consumes no additional space.

v  [Linux] RAID (be it hardware- or software-), assumes that if a write to a disk doesn't return an error, then the write was successful. Therefore, if your disk corrupts data without returning an error, your data will become corrupted. This is of course very unlikely to happen, but it is possible, and it would result in a corrupt filesystem. http://www.tldp.org/HOWTO/Software-RAID-HOWTO-6.html

ZFS related links:

Why ZFS for Home Moving ZFS pools ZFS root is near Zones on ufs vs. ZFS