Simple question, maybe

Simple question, maybe

[Jason Shelton]

Hello, I'm sorry to bother all of you with what may be a trivial
question, but I'm stumped. I work for a company that makes backup and
recovery software and we have a need to boot a kernel that has Raid
support built-in, but would like to tell the kernel not to autodetect
the raid devices that may be on the system. Is there a way to do this?
perhaps a lilo append string or something? 

Thanks for your time.

Jason Shelton
Storix Software

Re: Simple question, maybe

[Neil Brown]

On  June 26, jason@storix.com wrote:
> Hello, I'm sorry to bother all of you with what may be a trivial
> question, but I'm stumped. I work for a company that makes backup and
> recovery software and we have a need to boot a kernel that has Raid
> support built-in, but would like to tell the kernel not to autodetect
> the raid devices that may be on the system. Is there a way to do this?
> perhaps a lilo append string or something? 

 append="raid=noautodetect"

NeilBrown

Re: Simple question, maybe

[Jason Shelton]

That was exactly what I needed, thank you very much. Now, if I may,
where did you find that? I've been looking all over the place and kept
hitting dead ends.

Thanks again

Jason Shelton
Storix Software



On Wed, 2002-06-26 at 11:02, Neil Brown wrote:
 
>  append="raid=noautodetect"
> 
> NeilBrown
>

Re: Simple question, maybe

[Neil Brown]

On  June 26, jason@storix.com wrote:
> 
> That was exactly what I needed, thank you very much. Now, if I may,
> where did you find that? I've been looking all over the place and kept
> hitting dead ends.

Use the source, luke:
linux/drivers/md/md.c:

__setup("raid=", raid_setup);

and

static int __init raid_setup(char *str)
{
	int len, pos;

	len = strlen(str) + 1;
	pos = 0;

	while (pos < len) {
		char *comma = strchr(str+pos, ',');
		int wlen;
		if (comma)
			wlen = (comma-str)-pos;
		else	wlen = (len-1)-pos;

		if (!strncmp(str, "noautodetect", wlen))
			raid_setup_args.noautodetect = 1;
		pos += wlen+1;
	}
	raid_setup_args.set = 1;
	return 1;
}

NeilBrown

resync patch & Neil's recent patches

[bo]

Neil & Raiders,

I am using Debian 2.4.5 linux(for ARM ). The "resync" speed is about
26M/sec.
I have 8*120G HDDs so it takes about 24 hours.

I saw some bug fixes and improvement on this topic from
 http://marc.theaimsgroup.com/?l=linux-kernel&m=100876771508736&w=2

Q1: Can I apply this patch to my 2.4.5 linux?
Q2: Which linux2.4.x has this fix?

Q3: Neil released 22 + 3 patches a couple of weeks ago.
       Can I apply these pathes to 2.4.5?

       Which linux 2.4.x will include these fixes?

Q3: The default MAX resync speed is 200M/sec. I am getting about
       10 % of this default speed. Could anyone get it? Could I get
       this average speed when I apply these patches?

Thanks,

Bo

Re: resync patch & Neil's recent patches

[Neil Brown]

On Wednesday June 26, bo@sosnetwork.net wrote:
> Neil & Raiders,
> 
> I am using Debian 2.4.5 linux(for ARM ). The "resync" speed is about
> 26M/sec.
> I have 8*120G HDDs so it takes about 24 hours.
> 
> I saw some bug fixes and improvement on this topic from
>  http://marc.theaimsgroup.com/?l=linux-kernel&m=100876771508736&w=2

I don't think any of the patches that you mention are particularly
relevant to your problem.

Maybe if you give some more precise details of your setup??

Also, try
   echo 100000 > /proc/sys/dev/raid/speed_limit_min
does that help?

NeilBrown

Re: resync patch & Neil's recent patches

[bo]

Neil,

> > I saw some bug fixes and improvement on this topic from
> >  http://marc.theaimsgroup.com/?l=linux-kernel&m=100876771508736&w=2
>

According to log file(from above infor), it cleaned up many things related
with RESYNC, and had
some bug fixes. He mentioned it goes to linux2.5.x.

I think we should have the same changes to Linux 2.4.x, don't you?
If so which release should include them? Any problem to apply this patch
to my 2.4.5?

How about your patches(23+)? Can I apply them to my lINUX2.4.5?

> I don't think any of the patches that you mention are particularly
> relevant to your problem.
>
> Maybe if you give some more precise details of your setup??
>
> Also, try
>    echo 100000 > /proc/sys/dev/raid/speed_limit_min
> does that help?
>
> NeilBrown
>

I already use 100M  for speed _limit_min,  300M for speed _limit_max.
I could not notice a big difference from changing this values.

Q1: This value go back to the default at boot/reset,  Should I modify to
change this
       default value in "md.c"? By any config parameter?

Q2:  >hdparm -tT /dev/hdxx
          Timing buffer-cache reads: 52.24 MB/s
          Timing buffered disk reads: 24.43 MB/s

        The "resync" speed on the raid1 device with hdxx:  25.4MB/s.

        Do you think this speed is reasonable enough?

Thanks for your help,

Bo

Re: resync patch & Neil's recent patches

[Neil Brown]

On Friday June 28, bo@sosnetwork.net wrote:
> Neil,
> 
> > > I saw some bug fixes and improvement on this topic from
> > >  http://marc.theaimsgroup.com/?l=linux-kernel&m=100876771508736&w=2
> >
> 
> According to log file(from above infor), it cleaned up many things related
> with RESYNC, and had
> some bug fixes. He mentioned it goes to linux2.5.x.
> 
> I think we should have the same changes to Linux 2.4.x, don't you?

I don't think they were significant bugs.  resync works quite well in
2.4.  Well enough that I don't think it should be fiddled with too much.

> If so which release should include them? Any problem to apply this patch
> to my 2.4.5?

They won't work in 2.4 as they stand.  There were some major changes
to the block device layer in 2.5 and these patches require (and are
required by) these changes.

> 
> How about your patches(23+)? Can I apply them to my lINUX2.4.5?

No.  Same reason.  I might back-port the more significant ones, but
much of it was code-cleanliness rather than bug fixes.

> 
> I already use 100M  for speed _limit_min,  300M for speed _limit_max.
> I could not notice a big difference from changing this values.
> 
> Q1: This value go back to the default at boot/reset,  Should I modify to
> change this
>        default value in "md.c"? By any config parameter?

Don't modify md.c.  Just echo a number to the /proc file in a boot
script.

> 
> Q2:  >hdparm -tT /dev/hdxx
>           Timing buffer-cache reads: 52.24 MB/s
>           Timing buffered disk reads: 24.43 MB/s
> 
>         The "resync" speed on the raid1 device with hdxx:  25.4MB/s.
> 
>         Do you think this speed is reasonable enough?

You couldn't ask for better.  This speed looks fine.

NeilBrown