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liutas
1 Copper

md3000i virtual disk only from one controler

hi all,

this is my first post to Dell community. I'm strugling with a md3000i storage to make it work with linux box and do multipathing. The thing is that my box can see, partiion and mount VirtualDisk from the storage, but it works only with one controler. In other words storage is exporting VirtualDisk to my initiator, but somehow two controlers show different disks for the same wwid.

My situation: one server connected to md3000i via 2 utp cables to two iscsi controlers. I plan to add another server to the picture, but cannot get first working. The whole idea is to have smth similar to this picture: http://www.performancemagic.com/Dell1950_MD3000i_Xen_Debian_iSCSI_RDAC/index.html#overview ., except that I will not use switches.

Question:

- should I expect open-iscsi to get scsi devices from different controlers of the same storage with exactly the same (partitions, lun, size etc.) characteristics, as it can get dell access partions? any configuration tricks?

- can someone paste SMdevices and ll /dev/disk/by-path listing to compare with working multipathing implementation?

Here are detail explanations:

1. This is what I got with Dell tools. As you can see one disk is on preffered controler and other is on alternate. In my opinion they both must be identical, but they are not as you will see in next steps.
# SMdevices
Dell Modular Disk Storage Manager Devices, Version 10.01.A6.01
Built Mon Sep 22 09:20:05 CDT 2008
Copyright (C) 2006 - 2008  Dell Inc. All rights reserved.

  /dev/sdb (/dev/sg4) [Storage Array NLV-md3000i, Virtual Disk VIrtual_Disk_Test_1_100, LUN 11, Virtual Disk ID <60026b9000372ce9000006ff4b03cc96>, Preferred Path (Controller-1): In Use]
  /dev/sdc (/dev/sg6) [Storage Array NLV-md3000i, Virtual Disk Access, LUN 31, Virtual Disk ID <60026b9000372cf3000005384ac4961e>]
  /dev/sdd (/dev/sg7) [Storage Array NLV-md3000i, Virtual Disk VIrtual_Disk_Test_1_100, LUN 11, Virtual Disk ID <60026b9000372ce9000006ff4b03cc96>, Alternate Path (Controller-0): Not In Use]
  /dev/sde (/dev/sg8) [Storage Array NLV-md3000i, Virtual Disk Access, LUN 31, Virtual Disk ID <60026b9000372cf3000005384ac4961e>]

2. This is what I got then try to see what kernel thinks about my scsi devices. As you can see sdb device has got one partition while his counterpart has not, but both have the same lun from the same storage.
# ll /dev/disk/by-path/
total 0
lrwxrwxrwx 1 root root  9 2009-11-19 13:29
ip-192.168.130.101:3260-iscsi-iqn.1984-05.com.dell:powervault.md3000i.60026b9000372cf3000000004ac495c0-lun-11
-> ../../sdd  
lrwxrwxrwx 1 root root  9 2009-11-19 13:29
ip-192.168.130.101:3260-iscsi-iqn.1984-05.com.dell:powervault.md3000i.60026b9000372cf3000000004ac495c0-lun-31
-> ../../sde  
lrwxrwxrwx 1 root root  9 2009-11-19 13:29
ip-192.168.131.102:3260-iscsi-iqn.1984-05.com.dell:powervault.md3000i.60026b9000372cf3000000004ac495c0-lun-11
-> ../../sdb  
lrwxrwxrwx 1 root root 10 2009-11-19 13:29
ip-192.168.131.102:3260-iscsi-iqn.1984-05.com.dell:powervault.md3000i.60026b9000372cf3000000004ac495c0-lun-11-part1
-> ../../sdb1  
lrwxrwxrwx 1 root root  9 2009-11-19 13:29
ip-192.168.131.102:3260-iscsi-iqn.1984-05.com.dell:powervault.md3000i.60026b9000372cf3000000004ac495c0-lun-31
-> ../../sdc  


3. Multipath is showing that the path is down. I think it is a consequence from weird iscsi and storage behaviour.
# multipath -ll
mpath0 (360026b9000372cf3000005384ac4961e) dm-15 ,
[features=0][hwhandler=0]
\_ round-robin 0 [prio=1][enabled]
 \_ #:#:#:# sdc 8:32  [active][ready]
\_ round-robin 0 [prio=1][enabled]
 \_ #:#:#:# sde 8:64  [active][ready]
sdd: checker msg is "directio checker reports path is down"
mpath4 (360026b9000372ce9000006ff4b03cc96) dm-14 ,
[size=100G][features=0][hwhandler=0]
\_ round-robin 0 [prio=1][enabled]
 \_ #:#:#:# sdb 8:16  [active][ready]
\_ round-robin 0 [prio=0][enabled]
 \_ #:#:#:# sdd 8:48  [failed][faulty]


4. This is info from MDSM, whish clearly shows, that my virtual disk is only one controler (1), while access partition is on both. And that is why multipath can see both paths for access partition,but not for my virtual disk (see previous example)
PROFILE FOR STORAGE ARRAY: NLV-md3000i (09.11.23 16.44.46)
 
 
MAPPINGS (Storage Partitioning - Enabled (1 of 16 used))-------------------
 
 
   Virtual Disk Name        LUN  RAID Controller Module  Accessible by        Virtual Disk status   
   VIrtual_Disk_Test_1_100  11   1                       Host Group Xen1-Nav  Optimal               
   Access Virtual Disk      31   0,1                     Host Xen1-Dom0       Optimal               
   Access Virtual Disk      31   0,1                     Storage Array        Optimal               

5.this is info from iscsiadm tool which show that I have active sessions to both controlers.
# iscsiadm -m session
tcp: [1] 192.168.131.102:3260,2 iqn.1984-05.com.dell:powervault.md3000i.60026b9000372cf3000000004ac495c0
tcp: [2] 192.168.130.101:3260,1 iqn.1984-05.com.dell:powervault.md3000i.60026b9000372cf3000000004ac495c0

My setup is:

6. # iscsiadm -m session -P 1
Target: iqn.1984-05.com.dell:powervault.md3000i.60026b9000372cf3000000004ac495c0
        Current Portal: 192.168.131.102:3260,2                                 
        Persistent Portal: 192.168.131.102:3260,2                              
                **********                                                     
                Interface:                                                     
                **********                                                     
                Iface Name: iface1                                             
                Iface Transport: tcp                                           
                Iface Initiatorname: iqn.2009-10.nutricia.local:xen1.nutricia.local
                Iface IPaddress: 192.168.131.1
                Iface HWaddress: default
                Iface Netdev: eth3
                SID: 1
                iSCSI Connection State: LOGGED IN
                iSCSI Session State: LOGGED_IN
                Internal iscsid Session State: NO CHANGE
        Current Portal: 192.168.130.101:3260,1
        Persistent Portal: 192.168.130.101:3260,1
                **********
                Interface:
                **********
                Iface Name: iface0
                Iface Transport: tcp
                Iface Initiatorname: iqn.2009-10.nutricia.local:xen1.nutricia.local
                Iface IPaddress: 192.168.130.1
                Iface HWaddress: default
                Iface Netdev: eth2
                SID: 2
                iSCSI Connection State: LOGGED IN
                iSCSI Session State: LOGGED_IN
                Internal iscsid Session State: NO CHANGE

I can ping to both controlers of md3000i, as you can see from arp table.

# arp -n | grep 13
192.168.131.102          ether   00:26:b9:37:2c:ed   C                     eth3
192.168.130.101          ether   00:26:b9:37:2c:f5   C                     eth2

firmware

Current configuration                                              
      Firmware version:                             07.35.31.60       
      NVSRAM version:                               N1532-735890-005  
      EMW version:                                  03.35.G6.37       
      AMW version:                                  03.35.G6.37   
    

 

Thanks for all opinions

Liutauras

 

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4 Replies
mrokkam
3 Argentium

Re: md3000i virtual disk only from one controler

The MD3000i allows access to each virtual disk from one controller only at a time. Only at the time of failover does the alternate controller access the disk. I am not sure how that is being handled by the multipath driver as this is not a supported Dell OS or a supported Dell driver. In the dell driver, the alternate path is hidden and both paths are seen as device.

Also, the access LUN-31 should not be modified or deleted as this could cause you to lose access to the array.

Hope this helps...

-Mohan

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Dev Mgr
5 Iridium

Re: md3000i virtual disk only from one controler

To repeat/add to mrokkam, disable DM-MPIO and install the Dell multipathing driver for the MD3000i (called "rdac"). This may solve some (all?) issues too.

Member since 2003

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liutas
1 Copper

Re: md3000i virtual disk only from one controler

Thanks all for answers,

but the link I was reffering says that it is working and I follow the procedure discussed in that article:

http://www.performancemagic.com/Dell1950_MD3000i_Xen_Debian_iSCSI_RDAC/Multipathing.html

It is saying it works, am I missunderstanging something.

 

Liutauras

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Dev Mgr
5 Iridium

Re: md3000i virtual disk only from one controler

I'd suggest you read the Dell documentation if you want a supported setup. The support matrix can be found here 

<ADMIN NOTE: Broken link has been removed from this post by Dell>

(page 7 says "For servers to connect to the MD3000i they must be running the supported iSCSI initiator, operating system, network components, and the Dell MPIO or MPP driver.", and there is the link to the 2nd generation firmware documentation.

Member since 2003

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