showing posts tagged with 'san'
by lunarg on January 25th 2016, at 13:59
When using Microsoft Fail-Over Clustering with Cluster Shared Volumes or Clustered disks which are on a HP EVA storage box, you may run into a problem about the disk/volume only being accessible from one of the nodes of the failover cluster, usually the node on which the disk/volume was added. When trying to access the volume from another node (e.g. by moving the role using that volume to another node), the role will fail and complain that the disk/volume is not accessible. Moreover, in Disk Management, the disk is not accessible and does not show the size of the disk. This makes the use of a fail-over cluster rather useless as the role can only run on the one node that does have access to t  ...
by lunarg on September 25th 2015, at 11:56

Assuming you have not configured that specific port as an L-Port, this can happen where the HBA did not completely log on to the fabric. This issue has been known to happen on Emulex HBAs.

To resolve, simply disable and re-enable the port on the SAN switch:

portdisable <port-number>
portenable <port-number>
by lunarg on August 31st 2015, at 15:50
You can reclaim previously allocated but unused disk space from your virtual disks by returning unused SAUs to the disk pool.

In order to reclaim space, files must be permanently deleted from disk. Space can only be reclaimed on a per-SAU base, meaning that the entire SAU must be empty and zeroed before it can be returned. If a single byte is in use on a SAU, the entire SAU cannot be returned.

Space reclamation can be done on any type of virtual disk, but depending on the type, there are some factors to account for. In case of a mirrored or dual virtual disk, the disk cannot be in recovery mode and its sync should be "up to date".

Running reclamation simultaneously is possible i  ...
by lunarg on August 31st 2015, at 12:10
To reclaim space in virtual environments and thin provisioned storage facilities, SDelete from SysInternals is probably the most used tool on Windows to clear out unused space of a volume, allowing the SAN to release these data blocks back to the storage pool.

But while SDelete is robust, it has a few (minor) limitations:

It cannot handle mount points, only logical drives (i.e. volumes mounted on a logical drive letter).

It is rather slow on very large file systems.

I found an alternative online in the form of a Powershell script at this thread, written by David Tan, who in turn based it on a script found here.

The script creates an empty ("zeroed") 1 GB file and copies that f  ...
by lunarg on July 10th 2015, at 12:35

No_Light means there's no link on the port. Usually this indicates a problem with the physical wiring, either a faulty cable, or the TX/RX have been swapped.

No_Sync means there's a link on the port (so technically, wiring is okay), but there's a problem with the actual communication. The most common problem is a mismatch in speed on the switch port and the HBA on the other side. Your best bet would be to set the port's speed (temporarily) to auto-negotiate and see what speed is selected. If this does not work, try manually setting the port fixed to lower speeds.

showing posts tagged with 'san'
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