Skip to main content

Rescan dynamically the scsi bus (applicable to CX Clariion SAN infrastructure)

Rescan dynamically the scsi bus

I've been working for a while with a Dell - Clariion CX-300, and the best way to add new attached LUNs was always to reboot the server.
However, that procedure is not always the most acceptable if you're in a hurry or if just want to do some tests.
I found the procedure described above, in an outdated website, but worked very well in my case.

I also recommend to use rescan-scsi-bus.sh script with the options -lwc. Type rescan-scsi-bus.sh --help to see the description of each option.

/root/rescan-scsi-bus.sh
Host adapter 1 (qla2xxx) found.
Host adapter 2 (qla2xxx) found.
Scanning for device 1 0 0 0 ...
OLD: Host: scsi1 Channel: 00 Id: 00 Lun: 00
Vendor: DGC Model: LUNZ Rev: 0208
Type: Direct-Access ANSI SCSI revision: 04
Scanning for device 2 0 0 0 ...
OLD: Host: scsi2 Channel: 00 Id: 00 Lun: 00
Vendor: DGC Model: LUNZ Rev: 0208
Type: Direct-Access ANSI SCSI revision: 04
0 new device(s) found.
0 device(s) removed.



So I stoped powerpath and unload qla modules in order to restart the whole thing.
$ /etc/init.d/PowerPath stop
Stopping PowerPath: done
$ lsmod | grep qla
qla6312 119233 0
qla2xxx 165733 1 qla6312
scsi_transport_fc 12225 1 qla2xxx
scsi_mod 116941 5 sg,qla2xxx,scsi_transport_fc,megaraid_mbox,sd_mod
[root@pasargades /opt/Navisphere/bin]
$ modprobe -r qla6312 qla2xxx
[root@pasargades /opt/Navisphere/bin]
$ lsmod | grep qla



then reload the whole thing:

$ modprobe qla2xxx qla6312
[root@pasargades /opt/Navisphere/bin]
$ /etc/init.d/PowerPath start
Starting PowerPath: done



then it works, the kernel does see the new devices

$ cat /proc/scsi/scsi
Attached devices:
Host: scsi0 Channel: 00 Id: 06 Lun: 00
Vendor: PE/PV Model: 1x2 SCSI BP Rev: 1.0
Type: Processor ANSI SCSI revision: 02
Host: scsi0 Channel: 01 Id: 00 Lun: 00
Vendor: MegaRAID Model: LD 0 RAID1 69G Rev: 521S
Type: Direct-Access ANSI SCSI revision: 02
Host: scsi3 Channel: 00 Id: 00 Lun: 00
Vendor: DGC Model: RAID 5 Rev: 0208
Type: Direct-Access ANSI SCSI revision: 04
Host: scsi3 Channel: 00 Id: 00 Lun: 01
Vendor: DGC Model: RAID 5 Rev: 0208
Type: Direct-Access ANSI SCSI revision: 04
Host: scsi4 Channel: 00 Id: 00 Lun: 00
Vendor: DGC Model: RAID 5 Rev: 0208
Type: Direct-Access ANSI SCSI revision: 04
Host: scsi4 Channel: 00 Id: 00 Lun: 01
Vendor: DGC Model: RAID 5 Rev: 0208
Type: Direct-Access ANSI SCSI revision: 04
[root@pasargades /opt/Navisphere/bin]
$ fdisk -l

Disk /dev/sda: 73.2 GB, 73274490880 bytes
255 heads, 63 sectors/track, 8908 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 1 4 32098+ de Dell Utility
/dev/sda2 * 5 583 4650817+ 83 Linux
/dev/sda3 584 1220 5116702+ 83 Linux
/dev/sda4 1221 8908 61753860 5 Extended
/dev/sda5 1221 3770 20482843+ 83 Linux
/dev/sda6 3771 5682 15358108+ 83 Linux
/dev/sda7 5683 6192 4096543+ 82 Linux swap

Disk /dev/sdb: 676.4 GB, 676457349120 bytes
255 heads, 63 sectors/track, 82241 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/sdb doesn't contain a valid partition table

Disk /dev/sdc: 1395.8 GB, 1395864371200 bytes
255 heads, 63 sectors/track, 169704 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/sdc doesn't contain a valid partition table

Disk /dev/sdd: 676.4 GB, 676457349120 bytes
255 heads, 63 sectors/track, 82241 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/sdd doesn't contain a valid partition table

Disk /dev/sde: 1395.8 GB, 1395864371200 bytes
255 heads, 63 sectors/track, 169704 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/sde doesn't contain a valid partition table

Disk /dev/emcpowera: 676.4 GB, 676457349120 bytes
255 heads, 63 sectors/track, 82241 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/emcpowera doesn't contain a valid partition table

Disk /dev/emcpowerb: 1395.8 GB, 1395864371200 bytes
255 heads, 63 sectors/track, 169704 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Disk /dev/emcpowerb doesn't contain a valid partition table




REmarque: We can see that fdisk sees double path 'raw' devices ( /dev/sdb and /dev/sdd ) to a same device, which finnaly is presented by powerpath as /dev/emcpowera . All disk system command (fdisk etc ...) should now use that device in order to benefit the use of powerpath (load balancing and failover on our double attached FC ).//

The 'rescan' script shows that now:

$ /root/rescan-scsi-bus.sh
Host adapter 3 (qla2xxx) found.
Host adapter 4 (qla2xxx) found.
Scanning for device 3 0 0 0 ...
OLD: Host: scsi3 Channel: 00 Id: 00 Lun: 00
Vendor: DGC Model: RAID 5 Rev: 0208
Type: Direct-Access ANSI SCSI revision: 04
Scanning for device 4 0 0 0 ...
OLD: Host: scsi4 Channel: 00 Id: 00 Lun: 00
Vendor: DGC Model: RAID 5 Rev: 0208
Type: Direct-Access ANSI SCSI revision: 04
0 new device(s) found.
0 device(s) removed.
Labels:

Popular posts from this blog

AD LDS – Syncronizing AD LDS with Active Directory

First, we will install the AD LDS Instance: 1. Create and AD LDS instance by clicking Start -> Administrative Tools -> Active Directory Lightweight Directory Services Setup Wizard. The Setup Wizard appears. 2. Click Next . The Setup Options dialog box appears. For the sake of this guide, a unique instance will be the primary focus. I will have a separate post regarding AD LDS replication at some point in the near future. 3. Select A unique instance . 4. Click Next and the Instance Name dialog box appears. The instance name will help you identify and differentiate it from other instances that you may have installed on the same end point. The instance name will be listed in the data directory for the instance as well as in the Add or Remove Programs snap-in. 5. Enter a unique instance name, for example IDG. 6. Click Next to display the Ports configuration dialog box. 7. Leave ports at their default values unless you have conflicts with the default values. 8. Click N...
Read more

HOW TO EDIT THE BCD REGISTRY FILE

The BCD registry file controls which operating system installation starts and how long the boot manager waits before starting Windows. Basically, it’s like the Boot.ini file in earlier versions of Windows. If you need to edit it, the easiest way is to use the Startup And Recovery tool from within Vista. Just follow these steps: 1. Click Start. Right-click Computer, and then click Properties. 2. Click Advanced System Settings. 3. On the Advanced tab, under Startup and Recovery, click Settings. 4. Click the Default Operating System list, and edit other startup settings. Then, click OK. Same as Windows XP, right? But you’re probably not here because you couldn’t find that dialog box. You’re probably here because Windows Vista won’t start. In that case, you shouldn’t even worry about editing the BCD. Just run Startup Repair, and let the tool do what it’s supposed to. If you’re an advanced user, like an IT guy, you might want to edit the BCD file yourself. You can do this...
Read more

Fixing Tanzu Kubernetes Pod to External Services Connectivity Issues with NSX-T

Fixing Tanzu Kubernetes Pod to External Services Connectivity Issues with NSX-T Last month I got a call from a customer who was pulling their hair out over a networking issue. They had just deployed VMware Tanzu Kubernetes Grid on their vSphere with Tanzu environment, everything looked good in the dashboards, all pods were running, but their applications inside the pods could not reach external databases running on traditional VMs in the same datacenter. The frustrating part was that some pods could reach external services perfectly fine, while others would just timeout. There was no clear pattern. Let me tell you how we figured this out and fixed it. The Initial Problem Here is what the customer setup looked like: vSphere 8.0 with Tanzu enabled NSX-T 4.1.2 for networking Three Tanzu Kubernetes clusters running different microservices applications External PostgreSQL database running on traditional VMs (non-Kubernetes) External API services running on another se...
Read more