Many support-cases open with the line \”Host can\’t see storage\” which puts most of these cases in the \”configuration\” queue. My assumption is that if a host can\’t \”see\” storage it has never worked before so there must be some kind of config problem. So once in a while you\’ll see a case popping up […]
A less known "host-can\’t-see-storage" problem caused by FC-SP authentication failures. Read More »
Many support-cases open with the line \”Host can\’t see storage\” which puts most of these cases in the \”configuration\” queue. My assumption is that if a host can\’t \”see\” storage it has never worked before so there must be some kind of config problem. So once in a while you\’ll see a case popping up
A less known "host-can\’t-see-storage" problem caused by FC-SP authentication failures. Read More »
Since a couple of FOS versions ago Brocade wanted to fix the problem Fibre-Channel has by definition called credit back-pressure. The word \”problem\” overstated since in 99.99999% of all fabrics you\’ll never see this anyway. As you know Fibre-Channel is a deterministic architected type of network which requires devices to behave properly. The chaos theory
The Emergency Health Threat (EHT) on Brocade FC fabrics Read More »
Dual HBA\’s, Dual Fabrics, redundant cache, RAID-ed disks, dual controllers or switched matrices, HA X-bars, multipath software installed and all OS drivers, firmware, microcode etc etc is up-to-date. In other words you\’re all sorted and you can sleep well tonight. And then Murphy strikes…….. As I\’ve described in my previous articles it takes one single
The great misunderstanding of MPIO Read More »
Credit – who doesn\’t want to have lots of it at the bank According to Wikipedia the short definition in finance terms is : Credit is the trust which allows one party to provide resources to another party where that second party does not reimburse the first party immediately (thereby generating a debt, but instead arranges
One rotten apple spoils the bunch – 4 Read More »
In the previous 2 blog-posts we looked at some areas why a fibre-channel fabric still might have problems even with all redundancy options available and MPIO checking for link failures etc etc. The challenge is to identify any problematic port and act upon indications that certain problems might be apparent on a link. So how
One rotten apple spoils the bunch – 3 Read More »
As mentioned in my previous post it only takes a single device to really cause some serious havoc in a storage environment. Now, \”Why\”, you may ask, do we have all these redundant kit in our environment like dual fabrics, redundant controllers, dual HBA\’s , MPIO software etc whilst this \”slow drain device\” is the
One rotten apple spoils the bunch – 2 Read More »
Last week I had another one. A rotten apple that spoiled the bunch or, in storage terms, a slow drain device causing havoc in a fabric. This time it was a blade-center server with a dubious HBA connection to the blade-center switch which caused link errors and thus corrupt frames, encoding errors and credit depletion.
One rotten apple spoils the bunch – 1 Read More »
I attended Cisco Live this week in Melbourne. Since it was very close to home and Cisco was kind enough to provide me with an entry ticket. (Many thanks for this.) While strolling around the expo floor I ran into the nice people from Fluke Networks who were showing their testing equipment and of course
The importance of clean fibre optics Read More »
On many occasions I\’ve seen posts from storage administrator who mapped some luns to hosts and on the first use the entire pool got whacked with all bells and whistles going off. (Yes, we can control bells and whistles.:-)) The administrator did nothing wrong however he should have communicated with the server admin what the
Help, my Thin Provisioning is not working Read More »
