Dear all,

unfortunately I observe drastic drops in read-  performance when I connect LUNs >2.2T to our Centos 5.5 Servers. I suspect issues with the GUID Partition Table, since it happens reproducibly only on the LUNs >2.2T and goes back to normal performance when using a LUN <2T with "normal", Legacy MBR partitions.
All machines are CentOS 5.5 (and RHEL 5.5) on IBM Blades LS21/LS41, all LUNs via Brocade 4G FC Switches from a SUN 7310 Unified Storage, EXT3 filesystems with standard settings.

Any hints?

regards
Jens