There are two common problems when creating partitions in Linux on big storage arrays. The first is easy, and the warning message from fdisk is a bit of a giveaway:
WARNING: The size of this disk is 8.0 TB (7970004230144 bytes).
DOS partition table format can not be used on drives for volumes
larger than (2199023255040 bytes) for 512-byte sectors. Use parted(1) and GUID
partition table format (GPT).
The answer: use parted. Don’t have it? Install it!
In those days spirits were brave, the stakes were high, men were real men, women were real women and small furry creatures from Alpha Centuari were real small furry creatures from Alpha Centauri. (Douglas Adams, The Hitch-Hikers Guide to the Galaxy)
Another first today: my blog joins the majority of tech blogs which somewhere contain a Douglas Adams quote. I included this quote because my axiom for today is
A SCSI disk array should be a real SCSI disk array. Ditto iSCSI.
(there’s a reason I never became an author)
What I mean by this is that it should behave like a normal block device: a big bucket into which I can pour my data. Of how it organises that data I could not give a flying turd, but for the fact that the underlying structure should be completely transparent to me. It could engrave the data on glass statues of Leonard Cohen for all I care, as long as it’ll give it back to me in thirty milliseconds.
Update (6-Feb-2012): I am reliably informed that the next major release of SANsymphony-V (9.0) will include direct SNMP support, making this nasty procedure unnecessary. Hooray 🙂
It seems that every time I install a new product for production, I have to find new and amusing ways to monitor everything to make sure I’m alerted in case of untowardness. My monitoring solution has Nagios at its core, so I want every alarm and fault condition to appear in the same place.
I’m in the early stages of implementing SANsymphony-V, which—despite its clumsy name—is a rather clever way of presenting replicated storage to a vSphere cluster. It presents iSCSI LUNs to hosts while looking after all the replication and mirroring nastiness itself, hiding the physical storage from the rest of the infrastructure. I might write more about it when I’ve finished the implementation, but for now let’s look at monitoring.
It took me a long time to think of an appropriate title for this post. I didn’t want to upset anyone by calling their products ‘consumer grade’ when that’s not how they’re marketed, and I couldn’t think of a way to say ‘disk arrays that aren’t made by Oracle, HP, IBM or NetApp’ that didn’t somehow denigrate the competition. I toyed with ‘sub-prime’ but that has other unfortunate connotations 😛