ZFS Recommendations for a new server

[Stefan Parvu]

Hi,

> The new server has a 2 x 1TB RE4 3ware 9650SE RAID and I have friends that
> tell me is actually better to use ZFS RAID instead of HW RAID1. Is this
> true? Why so?

It depends. You need to measure your applications with and without hdw RAID. 
For example we are migrating some workloads from Debian 7 to FreeBSD 10 and 
ZFS. We are using LSI MegaRaid 2208 controller and SATA disks.  

We have tested on FreeBSD 10 different setups, see below:

1. HDW RAID 10 - UFS2

Seq Disk IO Test
                             5MB            500MB
F1.1    W     1.2 GB/sec    1.2 GB/sec
            R      1.2 GB/sec    3.9 GB/sec
						
Random Disk IO
                           500 Files     2500Files
F1. 2    RR    872 MB/sec     271 MB/sec
				
F1.3     RW   920 MB/sec    1065 MB/sec
            RR   1048 MB/sec   1089 MB/sec


2. HDW RAID 6 - UFS2

Seq Disk IO Test
                             5MB            500MB
F2.1    W     1.3 GB/sec    900 MB/sec
            R      1.0 GB/sec    3.8 GB/sec
						
Random Disk IO
                           500 Files     2500Files
F2. 2    RR    884 MB/sec     1188 MB/sec
				
F2.3     RW   760 MB/sec    79 MB/sec
             RR    866 MB/sec   90 MB/sec


3. RAIDZ2 Pool, 6 disks, ZFS		
                             2500 Files
 F3	RW            310 MB/sec
        RR             350 MB/sec


So for our applications it seems ZFS is faster. We need RAM for caching but that is not
a problem anymore.

Seq R -  Sequantial reading
Seq W -  Sequantial writting
RR  - Random Reads
RW - Random Writes

-- 
Stefan Parvu <sparvu at systemdatarecorder.org>