[Btrfs-devel] btrfs and Solid State Disks (SSD).

Miguel Figueiredo Mascarenhas Sousa Filipe miguel.filipe at gmail.com
Mon Feb 11 10:39:15 PST 2008

Hi there,

This might sound stupid, but since I cannot infer from the
documentation and features of btrfs the answer to my doubts.
Here it goes:

Is the data and metadata ondisk layout of btrfs favorable for SSDs ?
>From what I read, current SSD are characterized by:
- poor performance in random writes (because of block erasure)
- require wear leveling, even those that emulate sata/ide/scsi disk
with onboard wear leveling logic.
- excellent seek latency
- excellent read (random and sequential) performance.
- good at sequential writes.

I've read that journaling file systems are usually bad for SSD because
of (from what I suppose are) two things:
- increased "random" write load (journal + proper data)
- write hot spot on the journal, causing lots of write cycles on a
given set of blocks.

Theoretically, ext2 would be better for a SSD than ext3 because of these issues.

So, is the design of btrfs a good match for the peculiarities of SSDs ?

Kind regards,
patiently waiting for btrfs to mature and become the default linux filesystem ;D

Miguel Sousa Filipe

Miguel Sousa Filipe

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