On Mon, Dec 06, 1999 at 10:04:11AM -0600, Andrew Ryan wrote:
> On Sun, Dec 05, 1999 at 06:58:35PM +0100, Ard van Breemen wrote:
> > Linux averages about 20 MB/s reading and writing raid 5 with 3
> > scsi-disks using the ncr53c8xx driver for the sym53c895.
> > raid-1 on the ami and the mega averages about 2.5MB/s to 3MB/s.
> > The myles is not much faster.
> Have you tried changing the write mode in the megaraid setup?  The default
> mode is the "safe" write mode.  If you change it to the "unsafe" (if you
> have a UPS it isn't unsafe) it should help your speed.  I can't remember the
> wording for the option.
Yep, but it is not really helpful for a logging filesystem I guess...
It defeats the purpose, and that for only a 17% write speed increase.

as I promised, some stats:
pc=Some siemens server with 128MB's of ram.
ami=express-200 or something like that (466)
Mylex is comparable. Both 16MB of ram.
solaris==solaris 7 x86. Linux == rh61 install disk
ncr=53c895
================================================================================
solaris raid-5 ami
--------------------------------------------------------------------------------
File './Bonnie.2981', size: 419430400
              -------Sequential Output-------- ---Sequential Input-- --Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU  /sec %CPU
          400  2371 12.3  2587  5.3  2098  5.8 14183 84.4 13345 15.6 212.9  4.7
================================================================================
solaris/mylex/raid 5
--------------------------------------------------------------------------------
/backup/bonnie > /Bonnie/Bonnie -s 200
              -------Sequential Output-------- ---Sequential Input-- --Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU  /sec %CPU
          200  2025  9.6  2030  3.3   678  1.6 13634 80.1 19388 22.7 201.7  2.6
================================================================================
solaris/mylex/raid 1
--------------------------------------------------------------------------------
File './Bonnie.453', size: 209715200
              -------Sequential Output-------- ---Sequential Input-- --Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU  /sec %CPU
          200  3619 17.4  3876  7.2   477  1.2 10947 64.3 13978 19.0 113.1  2.0

================================================================================
solaris/ami/raid 1
--------------------------------------------------------------------------------
File './Bonnie.416', size: 419430400
              -------Sequential Output-------- ---Sequential Input-- --Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU  /sec %CPU
          400  3237 15.5  3936  6.4  4165 10.8 11991 70.3 10816 12.6 206.0  3.9
================================================================================
solaris/ami controller/raid 1
write back option turned on
--------------------------------------------------------------------------------
File './Bonnie.603', size: 419430400
              -------Sequential Output-------- ---Sequential Input-- --Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU  /sec %CPU
          400  4114 19.8  4697  7.9  3862 10.5 10224 59.8  8376 10.6 186.6  3.4
================================================================================
linux/mylex/raid 1 RH61 install media
"mke2fs -b 4096 -R stride=16 /dev/rd/c0d0" (Geen partitionering)
--------------------------------------------------------------------------------
File './Bonnie.46', size: 209715200
              -------Sequential Output-------- ---Sequential Input-- --Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU  /sec %CPU
          200  5287 73.5  5173  4.2  2926  5.9  6092 77.3 14655  8.4 349.6  3.5
================================================================================
linux/NCR controller/software raid 5 RH61 install media
"mke2fs -b 4096 -R stride=8 /dev/md0" (Geen partitionering)
(During rebuild of the raiddevice, 200Meg Bonnie)
--------------------------------------------------------------------------------
File './Bonnie.65', size: 209715200
              -------Sequential Output-------- ---Sequential Input-- --Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU  /sec %CPU
          200  6220 87.2 20083 17.1  7723 17.6  6855 88.9 21344 13.0 399.6  4.2
================================================================================
linux/NCR controller/software raid 5 RH61 install media
"mke2fs -b 4096 -R stride=8 /dev/md0" (Geen partitionering)
(During rebuild of the raiddevice, 400Meg Bonnie)
--------------------------------------------------------------------------------
              -------Sequential Output-------- ---Sequential Input-- --Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU  /sec %CPU
          400  6007 84.1 18349 16.1  7769 16.6  7172 92.5 21491 14.4 230.1  2.4
================================================================================
linux/NCR controller/software raid 5 RH61 install media
"mke2fs -b 4096 -R stride=8 /dev/md0" (Geen partitionering)
(After rebuild of the raiddevice, 400 Meg Bonnie)
--------------------------------------------------------------------------------
File './Bonnie.162', size: 419430400
              -------Sequential Output-------- ---Sequential Input-- --Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU  /sec %CPU
          400  6049 84.4 18215 15.5  7776 17.1  7192 93.2 21577 13.4 232.9  2.8
================================================================================
Resultaten:
linux/NCR controller/software raid 1 RH61 install media
"mke2fs -b 4096 -R stride=8 /dev/md0" (Geen partitionering)
(During rebuild of the raiddevice, 400Meg Bonnie)
--------------------------------------------------------------------------------
File './Bonnie.51', size: 419430400
              -------Sequential Output-------- ---Sequential Input-- --Random--
              -Per Char- --Block--- -Rewrite-- -Per Char- --Block--- --Seeks---
Machine    MB K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU K/sec %CPU  /sec %CPU
          400  6676 94.4 15419 13.9  6566 13.8  7238 92.8 14684 10.1 195.3  2.4
--------------------------------------------------------------------------------

Note: these figures are not good enough to base your choice of raidcontroller
on. And no, they should not be used as an authoritive test. Just look at the
numbers and think about them.
These are my conclusions:
1) software raid-5 with linux is definitely MUCH faster. Especially when we
realize that the rh61 install media uses the ncr53c8xx driver, and not the
sym53c8xx driver.
2) solaris ufs versus linux ext2...

My personal conclusion:
mylex and ami raid controllers have about the same performance.
Both have their pro's and con's. We choose ami as our first raid controller,
because at first it seemed to be the best supported for configuring empty
raid-controllers from within solaris. Myles is still on our list, but will
be worked on in the future as our second source.
(And, ehhhh, we use linux to install solaris :))), try booting solaris from
a cd...).

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