[DRBD-user] vSphere MPIO with scst/drbd in dual primary mode. WAS: Re: [Scst-devel] R: Re: virt_dev->usn randomly generated!?

Matteo Tescione matteo at rmnet.it
Sat Mar 6 19:43:35 CET 2010

Note: "permalinks" may not be as permanent as we would like,
direct links of old sources may well be a few messages off.


Hi folks,
after a little bit of experimenting I SUCCESFULLY created an drbd active/active cluster with scst/iscsi exported to round-robin vsphere initiator.

configuration is 2 virtual machines with centos5-64 linux-2.6.33 patched and drbd8.3.7. Initiators are vSphere Software iscsi initiator.
Relevant config in drbd is net section, allow-two-primaries.
Relevant config in scst.conf is:

DEVICE rmnet-devel,/dev/drbd0,NV_CACHE,512

[ASSIGNMENT Default_iqn.2010-02.com.scst:RMnet-devel]
#DEVICE <device name>,<lun
DEVICE rmnet-devel,0

Note that I'm using the same scst.conf and iscsi-scstd.conf in both targets.
The vSphere initiators are seeing 2 paths for 1 device, switched to Round-robin.
Since the targets are running virtual with no real hardware, i have no idea at the moment of what kind of performance increase it could bring.
Vlad, what do you think about? is fileio the best choice here?

Hope this helps,
--
matteo




----- Messaggio originale -----
Da: "Brian Jared" <bjared at ethosprime.com>
A: "Vladislav Bolkhovitin" <vst at vlnb.net>
Cc: scst-devel at lists.sourceforge.net
Inviato: venerdì 5 marzo 2010 19.54.51 (GMT+0100) Europe/Berlin
Oggetto: [SPAM?]Re: [Scst-devel] R: Re:  virt_dev->usn randomly generated!?

That was the intention...but the scst.conf file on the other machine looks
a lot different.  There's no [HANDLER vdisk] section, and only GROUP and 
ASSIGNMENT sections for the Default_iqn.x.x.x ... I'm guessing that's why
they didn't work?  Below is the config that is on the other host, but I
can't believe it's so different from the other one...  It's been a while,
so I am not sure what all I tried back then, or why this is so drastically
different.  

  --Brian

# Automatically generated by SCST Configurator v1.0.6.

[HANDLER disk]
#DEVICE <H:C:I:L>

[HANDLER disk_perf]
#DEVICE <H:C:I:L>

[GROUP Default]
#USER <user wwn>

[GROUP Default_iqn.2000-01.com.ethosprime:nas2.drbd0.bucket01]
#USER <user wwn>

[GROUP Default_iqn.2000-01.com.ethosprime:nas2.drbd1.bucket02]
#USER <user wwn>

[GROUP Default_iqn.2000-01.com.ethosprime:nas2.drbd2.bucket03]
#USER <user wwn>

[GROUP Default_iqn.2000-01.com.ethosprime:nas2.drbd3.bucket04]
#USER <user wwn>

[ASSIGNMENT Default]
#DEVICE <device name>,<lun>

[ASSIGNMENT Default_iqn.2000-01.com.ethosprime:nas2.drbd0.bucket01]
#DEVICE <device name>,<lun>
DEVICE 0:2:1:0,0

[ASSIGNMENT Default_iqn.2000-01.com.ethosprime:nas2.drbd1.bucket02]
#DEVICE <device name>,<lun>
DEVICE 0:2:2:0,0

[ASSIGNMENT Default_iqn.2000-01.com.ethosprime:nas2.drbd2.bucket03]
#DEVICE <device name>,<lun>
DEVICE 1:2:0:0,0

[ASSIGNMENT Default_iqn.2000-01.com.ethosprime:nas2.drbd3.bucket04]
#DEVICE <device name>,<lun>
DEVICE 1:2:1:0,0

[TARGETS enable]
#HOST <wwn identifier>

[TARGETS disable]
#HOST <wwn identifier>

----- Original Message -----
From: "Vladislav Bolkhovitin" <vst at vlnb.net>
To: "Brian Jared" <bjared at ethosprime.com>
Cc: scst-devel at lists.sourceforge.net
Sent: Friday, March 5, 2010 12:58:48 PM GMT -05:00 US/Canada Eastern
Subject: Re: [Scst-devel] R: Re:  virt_dev->usn randomly generated!?

Brian Jared, on 03/05/2010 06:57 PM wrote:
> I found my old config. For some reason I thought I deleted all of the old
> scst stuff.
> 
> This is what my config looked like before I gave up.  Those DEVICE lines
> appear just as you mentioned.  So, what did I do wrong?

Used the same file and scst_vdisk_ID on both hosts?

>   --Brian
> 
> # Automatically generated by SCST Configurator v1.0.6.
> 
> [HANDLER vdisk]
> #DEVICE <vdisk name>,<device path>,<options>,<block size>
> DEVICE bucket01,/dev/drbd0,NV_CACHE,512
> DEVICE bucket02,/dev/drbd1,NV_CACHE,512
> DEVICE bucket03,/dev/drbd2,NV_CACHE,512
> DEVICE bucket04,/dev/drbd3,NV_CACHE,512
> 
> [HANDLER vcdrom]
> #DEVICE <vdisk name>,<device path>
> 
> [GROUP Bucket01]
> #USER <user wwn>
> 
> [GROUP Bucket01_iqn.2000-01.com.ethosprime:nas1.drbd0.bucket01]
> #USER <user wwn>
> 
> [GROUP Bucket02]
> #USER <user wwn>
> 
> [GROUP Bucket02_iqn.2000-01.com.ethosprime:nas1.drbd1.bucket02]
> #USER <user wwn>
> 
> [GROUP Bucket03]
> #USER <user wwn>
> 
> [GROUP Bucket03_iqn.2000-01.com.ethosprime:nas1.drbd2.bucket03]
> #USER <user wwn>
> 
> [GROUP Bucket04]
> #USER <user wwn>
> 
> [GROUP Bucket04_iqn.2000-01.com.ethosprime:nas1.drbd3.bucket04]
> #USER <user wwn>
> 
> [GROUP Default]
> #USER <user wwn>
> 
> [ASSIGNMENT Bucket01]
> #DEVICE <device name>,<lun>
> 
> [ASSIGNMENT Bucket01_iqn.2000-01.com.ethosprime:nas1.drbd0.bucket01]
> #DEVICE <device name>,<lun>
> DEVICE bucket01,0
> 
> [ASSIGNMENT Bucket02]
> #DEVICE <device name>,<lun>
> 
> [ASSIGNMENT Bucket02_iqn.2000-01.com.ethosprime:nas1.drbd1.bucket02]
> #DEVICE <device name>,<lun>
> DEVICE bucket02,0
> 
> [ASSIGNMENT Bucket03]
> #DEVICE <device name>,<lun>
> 
> [ASSIGNMENT Bucket03_iqn.2000-01.com.ethosprime:nas1.drbd2.bucket03]
> #DEVICE <device name>,<lun>
> DEVICE bucket03,0
> 
> [ASSIGNMENT Bucket04]
> #DEVICE <device name>,<lun>
> 
> [ASSIGNMENT Bucket04_iqn.2000-01.com.ethosprime:nas1.drbd3.bucket04]
> #DEVICE <device name>,<lun>
> DEVICE bucket04,0
> 
> [ASSIGNMENT Default]
> #DEVICE <device name>,<lun>
> 
> [TARGETS enable]
> #HOST <wwn identifier>
> 
> [TARGETS disable]
> #HOST <wwn identifier>
> 
> 
> 
> ----- Original Message -----
> From: "Vladislav Bolkhovitin" <vst at vlnb.net>
> To: "Brian Jared" <bjared at ethosprime.com>
> Cc: scst-devel at lists.sourceforge.net, "Matteo Tescione" <matteo at rmnet.it>
> Sent: Friday, March 5, 2010 8:44:54 AM GMT -05:00 US/Canada Eastern
> Subject: Re: [Scst-devel] R: Re:  virt_dev->usn randomly generated!?
> 
> Brian Jared, on 03/04/2010 04:41 AM wrote:
>> Maybe you could give an example of a config that would generate
>> the same SN from two targets that MUST be different.  I'm very curious,
>> as I couldn't find any documentation on this.
>>
>> It's my understanding that targets must all be uniquely named, and unique
>> target names pushed through a static (randomly generated) array will also
>> be unique, and thus vSphere4 won't see them as being the same LUN on
>> different hosts.
>>
>> Again, the problem is that my only interface appears to be my naming of the
>> iSCSI target LUN, which has to be unique...so...they'll always appear like
>> 4 unique disks, and not two disks with two paths each.
>>
>> An example config might clear this up.  I'm still wondering how this works.
> 
> In SCST all devices have names. Matteo gave you example:
> 
> DEVICE devel-datastore,/dev/drbd0,NV_CACHE,512
> 
> Here "devel-datastore" is the name. From this name and _only from it_ 
> the ID/USN is generated.
> 
> Vlad
> 


-- 
; Brian Jared <bjared at ethosprime.com>
: Ethos Prime Engineer
: http://www.ethosprime.com
: Cell: 317.201.9036 

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