[CentOS] GPT Partitions >2.2T with Centos 5.5

Wed Jul 14 10:22:05 UTC 2010
Lars Hecking <lhecking at users.sourceforge.net>

Jens Neu writes:
> > I think ext3 is a bit slow on so big LUNS, try xfs or similar?
> there is no official support for xfs in RHEL5, so that is not an option. 
> Besides, I'm talking about a drop of >150mb/s to ~10mb/s read performance 
> when cracking the 2.2T size. This is clearly not in the ext3 (or FS for 
> that matter) magnitude of performance issues. Also, numbers stay the same 
> when dd'ing on the raw device (LUN).
 This may not be relevant for you at all, but I have seen a comparable drop in
 read performance on a new Dell machine (hdparm -t, 25MB/s vs. 130MB/s),
 completely unrelated to the disk type.  In this case, I had to add
 "pci=nommconf" to the kernel line in grub.conf.  This was specific to the RH
 kernel, live CDs with 2.6.32 or .34 kernels were fine. I also noticed that
 booting up older IBM Intellistations under CentOS gave a warning about a BIOS
 bug ("MCFG area at e0000000 is not E820-reserved"; whatever that means :) and
 not using mmconfig.

 Also make sure that all BIOS options are set correctly, if applicable.

This message and any attachments may contain Cypress (or its
subsidiaries) confidential information. If it has been received
in error, please advise the sender and immediately delete this