Web Server Statistics

JJB's Home Page

GIOD  Partners

Caltech's Centre for Advanced Computing Research

Caltech's HEP department

CERN's Information Technology Division

CERN's CMS experiment



3ware RAID arrays tests with Linux 2.4.19 on P4DPE with twin 2.4 GHz CPUs

Why are we doing these tests?

We have an opportunity to use a 10Gbit WAN between Sunnyvale and Chicago for testing. We want

to show 1 GByte/sec file transfers across this link. This means we need to put servers at each end

of the link that can source/sink that rate. We know we can achieve ~>200MByte/sec WAN speeds

using optimal TCP parameters and twin SysKonnect cards in a single server. So we need to find

a disk subsytem that can read/write at least 200 MByte/sec. Then we will put four or five of

them at each site. One challenge will be finding a hardware/software configuration that allows

simultaneously to hammer the NICs and the Disks at this rate.

Server Details

The hardware configuration is a Supermicro P4DPE-GE with dual
P4 2.4 GHz CPUs, 2GB ECC DDR RAM, twin 3ware 7850 IDE/RAID controllers.

Disks are sixteen 120GB Western Digital IDE 7200RPM attached to
3ware controllers, seventeenth is system disk.

3ware controllers are seated in slots #1 and #3 on the motherboard.

Software is Linux Red Hat 2.4.19 kernel. 
The 3ware drivers are version Firmware is version

Benchmarking software is bonnie++ version 1.02c.

bonnie++ command used for all measurements:

bonnie++ -d /raid -s:5000:64k -mServer -r2048 -x10 -u0 -f -q

All numbers are for block read and write speeds as reported
by Bonnie++ (which we independently verified with our own
benchmark code, showing the same numbers)
(In this image, the 3ware cards are in PCI slots 1 & 3. Better performance is obtained with the
cards in slots 1 & 6 i.e. not sharing the same PCI I/O controller.)
We purchased our systems from ACME Computer. Contact me if you'd like detailed information 
on the price (around $8k).

1) First with disks in RAID5 in 3ware, 64kB block size, software raid 0 device chunk size 512kB:

XFS filesystem: 		read  @ 140-202 MB/sec
                		write @ 80-88 MB/sec
(11 tests)

JFS filesystem: 		read  @ 180-207 MB/sec
                		write @ 62-73 MB/sec
(2 tests)
reiserfs filesystem: 	read  @ 145-177 MB/sec
                		write @ 106-107 MB/sec
(2 tests)
In general we note the wide variation in read rates in all the tests, 
and for all filesystem types.

2) Now using IRQ patch for Foster CPUs mentioned at:

XFS filesystem: 		read  @ 142-172 MB/sec
                		write @ 80-86 MB/sec
(2 tests)

We ran without this patch after noting these results.

3) Now with disks in RAID0 in 3ware, 64kB block size, software raid 0 device chunk size 512kB:

XFS filesystem: 		read  @ 189-198 MB/sec
                		write @ 160-168 MB/sec
(2 tests)

JFS filesystem: 		read  @ 209-218 MB/sec
                		write @ 117-152 MB/sec
(2 tests)
reiserfs filesystem: 	read  @ 188-189 MB/sec
                		write @ 139-140 MB/sec
(2 tests)

4) Repositioning one of the 3ware controllers to Slot 6 (133Mhz)

XFS filesystem: 		read  @ 224-255 MB/sec
                		write @ 181-193 MB/sec
(2 tests)

5) Using various chunk sizes in the software RAID

Using the XFS filesystem [except where indicated) (which has a 4kB blocksize).
Chunk size for software stripe (kB) Read speed (MB/sec) Write speed (MB/sec)
4 160-161 181-193
64 172-177 180-192
128 195-200 180-192
256 226-227 180-192
512 224-255 181-193
1024 190-249 180-191
512 (JFS) 256-256 (JFS) 149-173 (JFS)


6) Now with 3ware RAID0 arrays reconfigured to use 128kB chunks

512kB software stripe chunk size

XFS filesystem: 		read  @ 216-245 MB/sec
                		write @ 179-191 MB/sec
(2 tests)
JFS filesystem: 		read  @ 256-271 MB/sec
                		write @ 148-167 MB/sec
(2 tests)

The JFS read result is the best yet.

7) At suggestion of Dan Yocum: turn hyperthreading OFF in the BIOS

XFS filesystem: 		read  @ 213-224 MB/sec
                		write @ 179-187 MB/sec
(2 tests)
This mod appears (within measurement errors) to make little difference.

8) At suggestion of Bruce Allen, increase read-ahead parameters:

echo 256 > /proc/sys/vm/max-readahead

echo 128 > /proc/sys/vm/min-readahead

Result in table below: it seems to have improved the write speed!

Chunk size for software stripe (kB) Read speed (MB/sec) Write speed (MB/sec)
512 (without read-ahead mod) 224-255 181-193
512 (with above mod) 225-229 195-209

General comment: I'm quoting these B/W numbers to 3 digit accuracy, but don't believe they are more accurate than +/- 10 MB/sec.

9) Applied the following "Yocum Settings":

echo "# Configure bdflush params" >> /etc/sysctl.conf

echo "vm.bdflush = 100 1200 128 512 15 5000 500 1884 2" >> /etc/sysctl.conf

echo "#configure vm readahead for 3ware controllers" >> /etc/sysctl.conf

echo "vm.max-readahead = 256" >> /etc/sysctl.conf

echo "vm.min-readahead = 128" >> /etc/sysctl.conf

echo "# Increase the number of file handles" >> /etc/sysctl.conf

echo "fs.file-max = 32768 " >> /etc/sysctl.conf

echo "# Increase the amount of maximum shared memory" >> /etc/sysctl.conf

echo "kernel.shmmax=1073741824" >> /etc/sysctl.conf

Chunk size for software stripe (kB) Read speed (MB/sec) Write speed (MB/sec)
512 (without Yocum Settings) 224-255 181-193
512 (with Yocum Settings) 228-232 196-208

Again, some marginal improvement in write speed.

10) CPU Load

CPU loads are around 80% during the block read tests, and 88% during block write. I.e. 80/88% of each and both CPUs in the system, or 160/176% of the combined CPU. This leaves 20/12% of the system for the NICs ... which will be marginal, since we know that 1.8Gbits/sec on two NICs requires 23% of each CPU ....



We are not able to reproduce the excellent numbers described at:
It appears that the best performance for read-orientated and mixed 
workloads is obtained with JFS, for write-orientated XFS.
Julian Bunn (with many thanks to Jan Lindheim for the really tricky Linux work!), November 2002.