[NCLUG] 1TB Blocksize Limit?

DJ Eshelman dj at sgc-inc.net
Wed Aug 28 17:22:18 MDT 2002


Okay, Let's just jump into it since I can't think of anything clever.
My RedHat Advanced 
Server troubles continue!  Yay!

We finally found a FibreChannel card that works out of 
the box (pretty much), the QLogic QLA2310-CK 2Gbit over Copper HBA.  This was after not-so-
valiant efforts by Adaptec and the best wishes and demos from LSI (sorry guys, but it just 
don't work yet!)
So yay, I get the drivers loaded, everything looks good until I try to find 
the actual storage device (it's an Arena Indy 2600-FC chassis- a device that houses 16 120GB IDE 
drives and puts them into a RAID 5 Array (or whatever, there's a lot of optoins) with two Fibre 
Channel (2Gbit Copper) interfaces.
I dig a little deeper and it appears that the total size 
of the array is too large (1.6TB) for Linux.  This is news to me, so I call them up and confer with a 
few engineers.  We know the device works because when I split the drives into two 800GB 
'virtual' drives it sees them both, it apparently is a limitation of the Kernel in regards to 
blocksizes.  Apparently anything over 1TB is not supported by the Kernel I'm using (Advanced 
Server is up to 2.4.9-e.8).  Now, I'm an ignoramous when it comes to Kernel stuff, I will admit- 
when the tech started talking about 31 pointer bits per block number or whatever, I started 
drooling and reaching for my club to go hunt for dinner.  But this doesn't help matters since 
our goal was to have all 1.6TB of data usable all in one drive mount.
So does anyone out there 
have any ideas for me?  I'm about at wits end with this project and I swear my mind isn't working 
any more- it just flat gave up.
I can find plenty of 'data' on the web as far as XFS and 
filesystem limits, but according to RedHat this is a block device problem, not a filesystem 
problem.  The other 'gotcha' is that I can't really do any major modification to the Kernel and 
still get support.  At this point I'm about ready to say screw it, and go with whatever will get 
the job done.  Any ideas out there?
Keep in mind that this is an Intel Xeon (x86) system, so the 
obvious answers are moot (get a 64 bit platform, etc).

I appreciate it.

-DJ 
Eshelman
dj at sgc-inc.net

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