Linux 3.3 Kernel: Btrfs vs. EXT4

[AnonymousCoward]

Thanks. I can't wait for SSDs to become good and usable.

That behaviour is specific to Sandforce controllers though, not every SSD does that.

[neuron]

http://www.anandtech.com/show/5508/i...to-sandforce/7 - don't fill a complete Sandforce SSD with a compressed file system, or it's performance (and presumably lifetime) will decrease substantially.

Hm, very interesting drawback of filesystem compression...

[fackamato]

http://www.anandtech.com/show/5508/i...to-sandforce/7 - don't fill a complete Sandforce SSD with a compressed file system, or it's performance (and presumably lifetime) will decrease substantially.

Thanks. I can't wait for SSDs to become good and usable.

[AnonymousCoward]

http://www.anandtech.com/show/5508/i...to-sandforce/7 - don't fill a complete Sandforce SSD with a compressed file system, or it's performance (and presumably lifetime) will decrease substantially.

[fackamato]

emm, no - the write cycles are not 'ok'. The smaller the structure the less write cycles you get. Modern flash chips write cycles are pathetic.

Sure. Do you have a source that shows a rough estimated lifetime of a Sandforce SSD? (normal use)

If it's 5 years than even halfing that to 2.5 years is definitely OK. As always, it depends on your usage scenario.

I think Anandtech has something but I can't find it at the moment.

[difrost]

Check this out - https://lkml.org/lkml/2012/2/29/210

[difrost]

http://marc.info/?l=linux-ext4&m=133052231227201&w=2

oh look, btrfs a lot faster than ext4 in a real world example.

Well that's borked thread. Follow https://lkml.org/lkml/2012/2/29/210

As one can notice, ext4 does not keep layout close thus requires more seeks to get the data read. Despite that it makes certain operations slower it also will eat your HDD(s) faster.

-df

[energyman]

emm, no - the write cycles are not 'ok'. The smaller the structure the less write cycles you get. Modern flash chips write cycles are pathetic.

[fackamato]

no, you see 50gb used. But internally it is only say 40 gb, saving the flash chips from some dangerous write cycles.

Exactly. Personally I'd use compression anyway to save space, unless it hurt write performance by >50%. The lifetime of the SSDs is fine anways regardless, so this is the route I'd go

[energyman]

no, you see 50gb used. But internally it is only say 40 gb, saving the flash chips from some dangerous write cycles.