What RAID-1 setup should I use for FreeBSD 6.0?
This article will highlight the disk drive tests I ran on my
ASUS A8V Deluxe. I’m about
to set this machine up to do various things, including cross compiling (which I wrote about back in
October). I still haven’t finished what I wanted to do, which is set
up this machine with RAID-1 running FreeBSD 6.0. When I started, 6.0 had not yet been released.
Now I’m about to redo some of my work and expand the scope slightly.
Here is what I plan to do. I have some SATA and some IDE drives that I’m going to test on various configurations to see
what setup gives me the fastest results. I don’t expect the differences to be huge. This isn’t scientific. I’m just
using the hardware I have.
I will be testing the various configurations shown in the table below:
| – | n/a | – IDE | – | – | – |
The columns represent the type of RAID-1 I will be using. The mainboard offers both SATA and IDE RAID-1.
The 3Ware 7006-2 does only IDE, not SATA.
I will also be testing gmirror(8).
For the gmirror part, I will be using Dru’s recent article:
Using Software RAID-1 with FreeBSD.
And for kicks and giggles, I’ll also try just a plain old SATA and plain old IDE (i.e. no RAID-1).
All testing was done on the same machine. For each test I installed 6.0-RELEASE, did a cvsup
of both the ports and source tree. Then I did a build world and upgraded to 6.0-STABLE. Each
cvsup was against the same image of the repository (i.e. my local cvsup server, which I did not
update during the course of this testing) to ensure each system was running against the same STABLE.
With the system running on 6.0-STABLE, I then installed PostgreSQL 8.1 (along with some other packages),
and ran a simple test:
time psql freshports.org < freshports.sql
I am interested only in the elapsed time. I don't care about anything else. I want throughput. And I want
it fast.
I could have used a snapshot. I didn't. I could have used some other test. I didn't. I used what I had
and did a test that is both disk intensive and CPU intensive.
FYI: the FreshPorts database I'm using is the daily backup taken at 29 Dec 2005 at 03:41. The file is about
526MB.
At the time of the test, these packages were installed:
$ pkg_info bash-3.0.16_1 The GNU Project's Bourne Again SHell bison-1.75_2,1 A parser generator from FSF, (mostly) compatible with Yacc cvsup-without-gui-16.1h_2 General network file distribution system optimized for CVS gettext-0.14.5 GNU gettext package gmake-3.80_2 GNU version of 'make' utility joe-2.8_5 Joe's own editor libiconv-1.9.2_1 A character set conversion library m4-1.4.4 GNU m4 postgresql-client-8.1.1 PostgreSQL database (client) postgresql-contrib-8.1.1 The contrib utilities from the PostgreSQL distribution postgresql-server-8.1.1_1 The most advanced open-source database available anywhere
Special thanks to my local computer store
I want to mention a local computer store, which I only just discovered.
Over the Top Computing is only about
3km from my house, less if I cycle there. I dropped by there a few days before
Christmas to buy a USB cable, and would up getting an external SATA HDD enclosure
and the HDD to go into it. Not to mention a laptop drive/IDE convertor (just in case).
I happened to ask them if they knew where I could get a couple of drive trays for an
Antec Sonata case. They did. They had some in the back. And the special screws to
go with them. BONUS!
Why is this relevant to this article? I'm using those trays now. It's much easier to swap drives around than traditional
drive mounts. Drive rails would be nice, but they don't have the sound dampening provided by those rubber o-rings that you
can see. The drive and screws touch only the rubber, not the tray. That reduces vibration and noise. Nice feature.
OK, so where are the results?
I have only partial results. I plan to post at least one set of results per day over the next 6 days. Watch this space.
| 8m1.582s 7m58.955s 7m57.663s 7m58.238s 7m54.368s 7m 58.169s1 | n/a | - IDE | 9m49.503s 9m24.412s 9m51.016s 9m54.415s 9m51.696s 9m 46s2 | 9m2.393s 9m6.686s 9m5.781s 9m7.093s 9m4.330s 9m 5.25663,4 | 11m19.354s 11m49.021s 11m46.158s 11m47.002s 11m43.415s 11m 40.99s3 |
1 The two SATA drives used for the above were:
- Maxtor DiamondMax Plus 9 120GB SATA 7200 RPM 8MB Cache (details)
- Western Digital WD1200JS 120GB SATA 7200 RPM 8MB Cache (details)
2 The two IDE drives used for the above were:
- Seagate Barracuda - Model ST380011A 80 GB ATA 100 (details)
- Maxtor DiamondMax Plus 9 80 GB ATA/133 (details)
The above is not a good match; one was ATA/100, the other ATA/133. I'll redo that test with two identical Maxtors.
3 The two IDE drives used for the above were:
4 The original tests were mistakenly done against 6.0-RELEASE. The
following result are against 6.0-STABLE:
- 10m19.299s
- 10m48.184s
- 10m44.767s
- 10m49.755s
- 10m46.567s
- average: 10m 41.71s
The times shown in a particular column represent each test run. The last number in a particular cell of the
table is the average of the numbers above it.
So far, SATA onboard rules. But to be fair, each SATA drive has its own cable. The single IDE cable is shared
by two drives (that is the only setup for IDE RAID on this main board).
The last update occurred at: October 10 2012 13:28:01.
I just thought of something else I could try: compare i386 against amd64. I may do that if I have time.
I noticed that with one test you used identical drives, but with other tests you used different models and even brands of drives. i’ve read information on hackers@ and other sources in the past stating that when setting up a raid environment, you should try to use the same type of drives. Using drives with different performance characteristics can cause one drive to be "faster" most of the time and defeat the purpose. If you think about it, raid 1 must write data to both disks and can read from either one. Each vendor has different cache and write timings, etc.
That being said, I have a raid 1 setup using gmirror. At the time i setup the box, it was running 5.4 with a patched ata driver to support my sata controller. The onboard raid was not supported. I upgraded the machine to 6.0 release and noticed a large improvement in gmirror. The drives are identical SATA western digital 80gb drives with 8mb cache. (same model, etc) Performance since I upgraded to 6.0 release has been excellent. The array often beats my single ultra 160 seagate 6mb cache 72gb 10k drive.
I use two disks from different manufacturers to improve the reliability of the RAID array. If there is a defect in the drive, and both drives are different brands, you’re much less likely to have a double failure in a short period of time (i.e. you lose both drives).
—
The Man Behind The Curtain