top | item 14071029

Performance of Solaris' ZFS LZ4 Compression

48 points| d0vs | 9 years ago |jomasoftmarcel.blogspot.com

21 comments

order

DiabloD3|9 years ago

Please note: Oracle does not implement the same version of ZFS as everyone else does. Sun chose the OpenZFS project as the steward of ZFS, and Oracle chose to never integrate OpenZFS upstream into their version of Solaris (which it itself is also an incompatible fork of the actual Solaris steward project, Illumos née OpenSolaris).

Since OpenZFS already implements LZ4 compression (and has so for quite some time), this is yet another feature that, once enabled, will stop you from importing your incompatible pool into anything that actually implements ZFS.

kev009|9 years ago

That's not really accurate phrasing, Sun had no involvement in OpenZFS because it started after Sun no longer existed. Sun maintained OpenSolaris which served as the de facto implementation of ZFS. OpenZFS was started in response to Oracle discontinuing OpenSolaris and only doing further ZFS in private.

You are correct about incompatible features. Sun and Oracle use a monotonically increasing integer to note new ZFS versions. OpenZFS instead incremented the version to 5000 and now uses feature flags so it is possible to coordinate individual feature enablement between all the operating systems that support OpenZFS.

rincebrain|9 years ago

While I am a fond user of an OpenZFS-derived implementation, OpenZFS postdates Sun's last gasps of existence by several years.

[1] has the OpenZFS launch announcement in September 2013, [2] dates Sun's acquisition to January 2010, [3] has the last OpenSolaris derived bits coming out of Sun in November 2010.

[1] - http://open-zfs.org/wiki/Announcement

[2] - https://www.cnet.com/news/oracle-buys-sun-becomes-hardware-c...

[3] - https://en.wikipedia.org/wiki/OpenSolaris (I'd cite osol-discuss, but that mailing list was shut down with the rest of sun.com)

throwaway2048|9 years ago

I think its a bit much to pretend that oracle somehow doesn't have "real" ZFS and solaris, even if you dont like what they have done with them and they are incompatable.

CJefferson|9 years ago

This really is too brief a study (although it's obviously fine for someone to write a quick blog-post about whatever they want).

Most importantly, how fast is the disk? I suspect (but would benchmark if I really needed to know) that the effects of compressions will be greatly different on an older 7,200 rpm spinning disk, vs a modern SSD.

lathiat|9 years ago

It's a very good question because his copies are stupidly slow. Only 15MB/s. You could probably compress that in real time on a raspberry Pi!

It's a very poor test.

kalleboo|9 years ago

I remember SandForce-based SSDs used to do compression in the disk firmware, are there any current SSDs that do the same?

herf|9 years ago

Most people say lz4+ZFS is a net win and you should usually enable it by default.

The big "gap" is probably between lz4 and gzip. e.g., for compressing logs, where gzip compresses a lot more but is terribly slow.

I hope zstd could be used for this case someday: http://facebook.github.io/zstd/

dmit|9 years ago

I imagine zstd's license will hamper its corporate adoption, especially among the big players.

  The license granted hereunder will terminate,
  automatically and without notice, if you (or any
  of your subsidiaries, corporate affiliates or
  agents) initiate directly or indirectly, or take
  a direct financial interest in, any Patent
  Assertion: (i) against Facebook or any of its
  subsidiaries or corporate affiliates...
https://github.com/facebook/zstd/blob/dev/PATENTS

kev009|9 years ago

Intel's QuickAssist is about to be standard on Xeon E5 chipsets and can do very high scale gzip at the cost of a PCIe round trip. Intel published some patches to ZoL for this.

gtirloni|9 years ago

It must be fine on a small test system, with CPU idling, etc.

I've worked with a few "ZFS appliances" from Sun (256-512TB range, NFS/iSCSI shares, 1-2k clients) and would never enable any advanced features on those (compression, dedup, etc). They were awfully unstable when we did that.

Granted, that was 5 years ago but I don't see any indication this technology has evolved significantly with all the drama surrounding Oracle, licensing, forks, etc. Just not worth the trouble these days, IMHO.

feld|9 years ago

Conpression is fine. Dedup has always been the problem because it was rushed.