PERC3/DC and ext3

Seth Mos knuffie at
Wed Jun 26 11:20:01 CDT 2002

At 08:39 26-6-2002 -0500, Abe Hayhurst wrote:
>I had originally posted the question below to the linux-poweredge list, but
>got no response, and I have a box I am going to begin work on today. Does
>anyone know whether PERC3 in write-back mode with ext3 is stable?

I believe the original problem report was based on a PERC2 card and it was 
fixed in a later firmware update afaik. I have had no problems yet with the 

>Also what are the block size options under ext3 and what is the default
>block size? I know ext2 defaults to 1024k, but can also do 2048k or 4096k.

I believe historically 4K is used most (==pagesize on ia32)

>If you were selecting a RAID1 stripe size for a disk devoted exclusively to
>your /swap partition, what stripe size would be best? Standard 64K or would
>setting to 4096K be faster and allow more I/O's since this is the memory
>apge size that linux uses? My system has 1GB of RAM and will therefore have
>a 2GB swap partition.

A large stripe size will benefit the throughput achieved and it probably a 
good idea. Swap is always slow and if for some reason you fill half of it 
you want to be able to read it back fast.

If you are gonna fill half of your swap space chances are that you average 
program size might be a few MB as well. So it isn't about really small 
blocks anyway.

>  All my data (large files) will be on a separate RAID10
>volume with 128K srtipes. My /boot and my root partition will be on a
>separate RAID1 volume. What stripe size would be optimal for those

64K(default) or 128K will do just fine. And from other posts I understand 
that splitting the backplane does not give you any performance benefit.


It might just be your lucky day, if you only knew.

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