10 Reasons You Need to Look at ZFS - Page 2

 By Paul Rubens
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6. SSD Hybrid Storage Pools

High performance SSDs can be added to a storage pool to create a hybrid storage pool. When these are configured as high performance cache disks, ZFS uses them to hold frequently accessed data to improve performance. It also uses a technology called L2 ARC (adaptive replacement cache) to write data that has to be stored immediately. This can slowly be moved over to conventional hard drives for more permanent storage when time and resources allow.

7. Capacity

ZFS is a 128-bit file system, which means that in theory it could store 256 quadrillion ZB (a ZB is a billion TB.) In practice this is larger than would ever be necessary, for the foreseeable future at least.

8. Data Scrubbing

ZFS can be made to scrub all the data in a storage pool, checking each piece of data with its corresponding checksum to verify its integrity, detect any silent data corruption, and to correct any errors in encounters where possible.

When the data is stored in a redundant fashion — in a mirrored or RAID-type array — it can correct any corrupt data it detects invisibly and without any administrator intervention. Since data corruption is logged, ZFS can bring to light defects in memory modules (or other hardware) which cause data to be stored on hard drives incorrectly.

Scrubbing is given low I/O priority so that it has a minimal effect on system performance, and can operate while the storage pool that is being scrubbed is in use.

9 . Simple, Efficient Administration

Using ZFS commands you can administer a system with short, efficient commands. For example, a five disk RAIDZ array could be set up with the single command:

zpool create poolname raidz c1t0d0 c2t0d0 c3t0d0 c4t0d0 c5t0d0

10. More on the Way

ZFS is still evolving, and new features will appear regularly. The roadmap for 2009 includes encryption for increased security, and data deduping to increase storage efficiency.

If you are interested in trying ZFS out then the easiest way is to get started is to download OpenSolaris or related distro from http://opensolaris.org/os/downloads/. There is also a ZFS for FUSE/Linux project, and you can watch ZFS: A hands on tutorial.

This article was originally published on Oct 7, 2009
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