Tag Archives: tips

StorNext labels gone? DON’T panic!

Topic

In SAN environments labels are often used to address a specific LUN, rather than using the device identifiers or numbers, to simplify the addressing of devices. Plus, a device does not have to be tied to a unique device number/id.

Losing a label due to a crash, or a defective hardware part or simply because a client overwrote the label, leaves the administrator in a quite scary und definitely uncomfortable situation. Data can’t be accessed or could even be lost.

Continue reading

StorNext performance: Allocation fill or round robin?

Topic

There are many ways to configure and optimize your file system under StorNext, and one option that makes (or can make) a difference is the allocation strategy. Which setting to use depends on your storage and the type of content you create. For the media and entertainment world we talk about unstructured data.

For the sake of this example, I create an imaginary setup with a StorNext based MDC and one 24bay RAID (dual controller) with 2 x 24bay expansion chassis. Continue reading

StorNext metadata slowness

Topic

As the  SAN environment contains many moving parts from the storage subsystem, fibre channel HBA’s, SFP’s, optical wire, the FC and Ethernet switch all the way to the metadata disks and the StorNext file system from Quantum it cannot really be called trivial. Every now and then you may struggle with performance issues that might be caused by any part mentioned above.
In such a complex environment you need to have some troubleshooting skills or you will end up ripping your hair out. Although there are many parts, I am going to focus on the StorNext metadata side in this article as I have seen it a few times now and users ended up remaking the file system.

Situation

Your SAN is working as expected with a decent performance; however, suddenly you hear from your users that browsing a folder takes a loooong time. Continue reading

StorNext cvfsck free space fragmentation

Situation

Many StorNext users have a handful of tools that come with the default StorNext installation, basic or full blown with interface.

One of those tools which can assist in troubleshooting is cvfsck. The most common use of cvfsck is to verify the file system itself. It’s a simple and powerful command line tool if you use it for the right reasons.

Details

Checking the health of the file system can be done when the file system if active but not really recommended as the journal is updated frequently. It’s basically a sanity check which may lead you to the action to take the file system offline. Continue reading

Short-Sizing StorNext (cvfs) LUNs

Situation

Every now and then you may have seen it or never have … lucky you. Under certain circumstances you may face the problem that you have configured your RAID with the same LUN size or even have used the wizard of the RAID vendor and StorNext (and other tools) will show you a different size on the LUNs in the OS.

Details

As a starting point, let’s assume our configured RAID provides 4 LUNs to the system. Two of those LUNs have a sector size of 9065074317 and two LUNs have a sector size of 9065074333. This can be seen in the output of /usr/bin/cvfs/cvlabel -l as follows: Continue reading