ext3 freeze / thaw

Two questions:

Which filesystems on SLES11 supports the freeze / thaw function for snapshots?
Can xfs_freeze be used on ext3/4 filesystems?

From the man page “xfs_freeze is intended to be used with volume managers and hardware RAID devices that support the creation of snapshots.” it’s only for xfs so no it can’t be used with ext3/4 filesystems.

btrfs supports snapshots, but you need to read the release notes for SP2;

You need to look at (the man page) fsfreeze - suspend access to an filesystem (Linux Ext3/4, ReiserFS, JFS, XFS).