On Mon, Aug 22, 2011 at 2:17 PM, C Anthony Risinger <anthony@xtfx.me> wrote:
On Mon, Aug 22, 2011 at 1:39 PM, Simon Schneider <schneida.simon@gmail.com> wrote:
Hi
I was about to use btrfs for my new SSD but I couldn't find any reason why I shouldn't stay with my normal LVM and ext4 setup. Is there any particular reason why everyone is so crazy about that new fs?
for me at least i like how simple it is to try stuff ... one of my favorite features is throwaway snapshots for testing various *whatever*. i can setup a chroot and instantly clone it and throw away just as fast; IIRC `mkchrootpkg` does this by default it it detects btrfs.
LZO compression on my eee s101 netbook (32GB "aftermarket" Runcore SSD) has made a *definite* difference in system performance.
... and also a simple rsync (inplace) script can give you fast/efficient "folding"/differential backups with very little work (and this will work even better once offline [or online i guess] de-dup is rocking)
i also use btrfs *heavily* in conjunction with namespace containers (eg, lxc-tools and friends) -- btrfs is the perfect companion. i can create hundreds of development/staging/production containers in seconds (if i actually needed them that fast ;-). it's the realization of namespaces at FS level.
i dont know much about LVM or soft-raid setups, and im sure much of the above can be achieved with --bind mounts, layers of this-and-that ... but btrfs is simple and effective. lastly -- and this is maybe a growing trend -- LVM works at the block level whereas btrfs is object level; btrfs can have object policies (eg RAID) with some objects partially in one state or another (eg compression), intelligent rebuilds (doesn't have to behave like a generic/dumb block device) ... this means things like RAID1 only EVER have 2 copies of an object ... even if there are 15 disks each object will only have 2 complete copies so space can be utilized more effectively ... this also helps to make full use of arrays with mismatched disk sizes/capabilities. <---(these last bits were discussed on the list recently, and i may be stating it incorrectly. by all means, correct me if necessary)
while i haven't personally (er... knowingly ;-) experienced any problems, it's appropriate to mention that recently there have been some reports of silent data-corruption in some setups. i dont think the exact cause is known yet ... but it also sounds like the new btrfsck will tackle much of it. ... tbh, unless you want to get a feel for it, are ready to troubleshoot, or have a specific use-case -- and have some other backup systems in place -- you'll probably just want to roll with "the usual" for now. -- C Anthony