max number of paths

max number of paths

[Charlie Sharkey]

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Is there a maximum number of paths supported by the device mapper ?

I have a setup with 12 paths to 14 luns. I had to reduce the number of
paths

to 10 for the device mapper to startup correctly.

 

 

 

 


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Re: max number of paths

[guy keren]

Charlie Sharkey wrote:
>  
> 
> Is there a maximum number of paths supported by the device mapper ?
> 
> I have a setup with 12 paths to 14 luns. I had to reduce the number of paths
> 
> to 10 for the device mapper to startup correctly.

i have seen such problems with linux kernel 2.4, long ago, when max SCSI 
disk devices was 256 (and hence - also max paths for such devices).

if you're not using SCSI, but rather some other type of device - it 
could be a limitation of the specific low level driver.

which kernel are you using? and which linux distribution? and what kind 
of block devices do your disks reside on?

--guy

Re: max number of paths

[Charlie Sharkey]

I'm seeing this on a Suse Sles10 x86_64 system, 2.6.16.60-0.34-smp.
I have a qlogic qle2462 connected to a hp eva back end. 



-----Original Message-----
From: dm-devel-bounces@redhat.com [mailto:dm-devel-bounces@redhat.com]
On Behalf Of guy keren
Sent: Monday, March 15, 2010 4:15 PM
To: device-mapper development
Subject: Re: [dm-devel] max number of paths


Charlie Sharkey wrote:
>  
> 
> Is there a maximum number of paths supported by the device mapper ?
> 
> I have a setup with 12 paths to 14 luns. I had to reduce the number of
paths
> 
> to 10 for the device mapper to startup correctly.

i have seen such problems with linux kernel 2.4, long ago, when max SCSI

disk devices was 256 (and hence - also max paths for such devices).

if you're not using SCSI, but rather some other type of device - it 
could be a limitation of the specific low level driver.

which kernel are you using? and which linux distribution? and what kind 
of block devices do your disks reside on?

--guy

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Re: max number of paths

[guy keren]

do the devices look something like /dev/sd*, or /dev/cciss/* or 
something similar? if the later - it _could_ be a driver-specific issue, 
and i would look for info about the specific block driver.

--guy

Charlie Sharkey wrote:
> I'm seeing this on a Suse Sles10 x86_64 system, 2.6.16.60-0.34-smp.
> I have a qlogic qle2462 connected to a hp eva back end. 
> 
> 
> 
> -----Original Message-----
> From: dm-devel-bounces@redhat.com [mailto:dm-devel-bounces@redhat.com]
> On Behalf Of guy keren
> Sent: Monday, March 15, 2010 4:15 PM
> To: device-mapper development
> Subject: Re: [dm-devel] max number of paths
> 
> 
> Charlie Sharkey wrote:
>>  
>>
>> Is there a maximum number of paths supported by the device mapper ?
>>
>> I have a setup with 12 paths to 14 luns. I had to reduce the number of
> paths
>> to 10 for the device mapper to startup correctly.
> 
> i have seen such problems with linux kernel 2.4, long ago, when max SCSI
> 
> disk devices was 256 (and hence - also max paths for such devices).
> 
> if you're not using SCSI, but rather some other type of device - it 
> could be a limitation of the specific low level driver.
> 
> which kernel are you using? and which linux distribution? and what kind 
> of block devices do your disks reside on?
> 
> --guy
> 
> --
> dm-devel mailing list
> dm-devel@redhat.com
> https://www.redhat.com/mailman/listinfo/dm-devel
> 
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