Feature
|
ZFS
|
BTRFS
|
COW (copy on write)
|
yes
|
yes
|
Snapshots
|
yes
|
yes
|
Performance degradation at near 98-100% disk usage
|
yes
|
Currently does kernel oopse, but being worked on
and honestly will probably have similar issue. (Someone ping me when
this is fixed)
|
Block level compression
|
yes
|
yes. Currenly only available as a mount option. *Maintenance nightmare*
|
Full on disk encryption (file, attributes, name.. etc)
|
Being worked on, but not production ready. Sun
recently revised their release schedule from May to probably some time
in 2009. (I'm just guessing on this timeline) Using solaris lofi encryption is possible in the mean-time.
|
Planned, but no certain schedule. Is limited to file bodies, but ecryptfs may also offer additional options
|
Spindle write balances
|
yes
|
Planned - no schedule
|
Online resizing
|
no (being worked on)
|
yes
|
Online defragmentation
|
no (ties into the same code as pool resizing so being worked on)
|
yes
|
shared library interface
|
libzfs
|
none.. no plans, but may be possible?
|
Alternative compression capability
|
yes, but would need to link into the kernel
|
yes, but would need to link into the kernel |
Aggressive file caching
|
yes
|
various kernel options.. (Unclear to the author what these options are or exactly do.. check /proc/sys/vm for whatever hackery)
|
Ditto block
|
yes (multiple copies of metadata and files logically distributed across all spindles. Number of copies of the default is tunable.)
|
metadata only |
write checksums
|
yes
|
yes
|
Built-in raid (More notes below)
|
0,1,10, 5 with fixes write hole (raidz), and some variant of 6 called raidz2
|
0,1 and 10
|
Automatically turns off write cache when not controlling full disk
|
yes
|
no
|
Easy way to transport pools/volumes between hosts
|
yes (zfs send/recieve)
|
Mirroring will be available, but I don't think this is the same as zfs send/receive
|
Primary sponsoring company
|
Sun™
(I think Sun™ should encourage the community to be more involved?)
|
Oracle™, RedHat™, HP™, IBM™, Intel™, Novell™and Linux community
|
License
|
CDDL
|
GPL2
|
ACL
|
yes (pure ACL.. all files have ACL) with userland support
|
yes,
but can be turned off? (but.. the gnu utils chmod and others may not have full support acl
yet.)
|
ACL model
|
NFSv4 ACL
|
Posix
|
| Endian independent
|
Yes.. swap a drive been sparc or intel as you wish
|
No
|
| separate zil
|
Yes
|
No
|
| separate l2arc
|
Yes
|
No
|
| zfs supports case-insensitive filesystems for Windows compatibility
|
Yes
|
No
|
| enforce utf-8-only filenames |
Yes
|
No
|
| direct io support |
Yes
|
Writes yes. Reads No - Planned
|
| POSIX compliant concurrent writes (single writer locks)
|
Yes
|
No |
Extended attributes
|
Yes
|
Yes
|
| Quotas
|
Yes
|
Yes
|
|
|
|
Favorite Quote from lead developer
|
"When
I take on a new problem is that I'm not interested in how it's been
done before. I only want to know, of all the constraints people tend to
assume, which ones are actually fundamental and which ones are just
habit?"
Jeff Bonwick
|
"something lame that gets us 85% of the way there is fine"
Chris Mason
|
**Warning some opinion**
RAID/volume management
|
Inside ZFS
|
Managed
outside the filesystem
Is lvm really good at managing
raid? Does it make the /problem/ more simple or add layers to the
administration which are a pita
|
