106 lines
4.4 KiB
HTML
106 lines
4.4 KiB
HTML
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">
|
||
|
<HTML>
|
||
|
<HEAD>
|
||
|
<META NAME="GENERATOR" CONTENT="SGML-Tools 1.0.9">
|
||
|
<TITLE> Linux DPT Hardware RAID HOWTO : Usage</TITLE>
|
||
|
<LINK HREF="DPT-Hardware-RAID-HOWTO-6.html" REL=next>
|
||
|
<LINK HREF="DPT-Hardware-RAID-HOWTO-4.html" REL=previous>
|
||
|
<LINK HREF="DPT-Hardware-RAID-HOWTO.html#toc5" REL=contents>
|
||
|
</HEAD>
|
||
|
<BODY>
|
||
|
<A HREF="DPT-Hardware-RAID-HOWTO-6.html">Next</A>
|
||
|
<A HREF="DPT-Hardware-RAID-HOWTO-4.html">Previous</A>
|
||
|
<A HREF="DPT-Hardware-RAID-HOWTO.html#toc5">Contents</A>
|
||
|
<HR>
|
||
|
<H2><A NAME="s5">5. Usage</A></H2>
|
||
|
|
||
|
<H2><A NAME="ss5.1">5.1 fdisk, mke2fs, mount, etc.</A>
|
||
|
</H2>
|
||
|
|
||
|
<P> You can now start treating the RAID as a regular disk. The first
|
||
|
thing you'll need to do is partition the disk (using fdisk). You'll
|
||
|
then need to set up an ext2 filesystem. This can be done
|
||
|
by running the command:
|
||
|
<P>
|
||
|
<BLOCKQUOTE><CODE>
|
||
|
<PRE>
|
||
|
% mkfs -t ext2 /dev/sdxN
|
||
|
</PRE>
|
||
|
</CODE></BLOCKQUOTE>
|
||
|
<P>where /dev/sdxN is the name of the SCSI partition. Once you do this,
|
||
|
you'll be able to mount the partitions and use them as you would any
|
||
|
other disk (including adding entries in /etc/fstab).
|
||
|
<H2><A NAME="ss5.2">5.2 Hot swapping </A>
|
||
|
</H2>
|
||
|
|
||
|
<P> We first tried to test hot swapping by removing a drive and putting
|
||
|
it back in the DPT-supplied enclosure/tower (which you buy for an
|
||
|
additional cost). Before we could carry this out to completion, one
|
||
|
of the disks failed (as I write this, the beeping is driving me
|
||
|
crazy). Even though one of the disks failed, all the data on the RAID
|
||
|
drive was accessible.
|
||
|
<P> Instead of replacing the drive, we just went through the motions
|
||
|
of hot swapping and put the same drive back in. The drive rebuilt
|
||
|
itself and everything turned out okay. During the time the disk had
|
||
|
filed, and during the rebuilding process, all the data was
|
||
|
accessible. Though it should be noted that if another disk had failed,
|
||
|
we'd have been in serious trouble.
|
||
|
<H2><A NAME="ss5.3">5.3 Performance </A>
|
||
|
</H2>
|
||
|
|
||
|
<P> Here's the output of the Bonnie program, on a 2144 UW with 9x3=17
|
||
|
GB RAID 5 setup, using the EATA DMA driver. The RAID is on a dual
|
||
|
processor Pentium Pro machine running Linux 2.0.33. For comparison,
|
||
|
the Bonnie results for the IDE drive on that machine are also given.
|
||
|
<P>
|
||
|
<BLOCKQUOTE><CODE>
|
||
|
<PRE>
|
||
|
-------Sequential Output-------- ---Sequential Input-- --Random--
|
||
|
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
|
||
|
MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
|
||
|
RAID 100 9210 96.8 1613 5.9 717 5.8 3797 36.1 90931 96.8 4648.2 159.2
|
||
|
IDE 100 3277 32.0 6325 23.5 2627 18.3 4818 44.8 59697 88.0 575.9 16.3
|
||
|
</PRE>
|
||
|
</CODE></BLOCKQUOTE>
|
||
|
<P> Some people have disputed the above timings (and rightly so---I've
|
||
|
been unable to try it out on our machines since they're completely loaded)
|
||
|
because the size of the file used may have led to it being cached
|
||
|
(resulting in an unusually good performance report). Here are some
|
||
|
timings with a 3344 UW controller:
|
||
|
<P>
|
||
|
<BLOCKQUOTE><CODE>
|
||
|
<PRE>
|
||
|
-------Sequential Output-------- ---Sequential Input-- --Random--
|
||
|
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
|
||
|
MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
|
||
|
1000 1714 17.2 1689 6.0 1200 5.7 5263 40.2 7023 12.1 51.3 2.2
|
||
|
</PRE>
|
||
|
</CODE></BLOCKQUOTE>
|
||
|
<P>And here are some timings on a SCSI-to-SCSI RAID system:
|
||
|
<P>
|
||
|
<BLOCKQUOTE><CODE>
|
||
|
<PRE>
|
||
|
-------Sequential Output-------- ---Sequential Input-- --Random--
|
||
|
-Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
|
||
|
MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU /sec %CPU
|
||
|
64 7465 100.0 70287 98.7 37012 97.7 8074 99.2 *****100.3 ***** 196.6
|
||
|
128 7289 99.3 67595 98.5 35294 98.6 7792 97.6 *****100.3 ***** 195.8
|
||
|
256 7222 98.8 44844 69.6 16096 51.8 5787 72.7 ***** 99.8 ***** 85.2
|
||
|
512 7138 98.4 13871 23.2 7888 29.3 7183 89.3 16488 27.2 1585. 11.5
|
||
|
1024 6908 95.8 12270 21.5 7161 25.4 7373 90.4 16527 28.2 123.8 1.8
|
||
|
2047 6081 84.1 12664 22.6 7191 25.6 7289 89.5 16573 28.5 75.0 1.2
|
||
|
|
||
|
***** results exceed column width (> 100 MB/sec, > 10000 seeks/sec)
|
||
|
|
||
|
host: Dual PII 400 MHz, 2 x U2W, 512 MB RAM, no internal disks
|
||
|
RAID: IFT 3102 UA 128 MB Cache, RAID-5, 6 x 9 GB
|
||
|
OS: SuSE Linux 6.0 with Kernel 2.2.3
|
||
|
</PRE>
|
||
|
</CODE></BLOCKQUOTE>
|
||
|
<HR>
|
||
|
<A HREF="DPT-Hardware-RAID-HOWTO-6.html">Next</A>
|
||
|
<A HREF="DPT-Hardware-RAID-HOWTO-4.html">Previous</A>
|
||
|
<A HREF="DPT-Hardware-RAID-HOWTO.html#toc5">Contents</A>
|
||
|
</BODY>
|
||
|
</HTML>
|