if you are on windows - what about downloading and installing lzop (e.g. putting to c:\windows) and adding something like this to the registry:

type lzop-context-menu-handler.reg

Windows Registry Editor Version 5.00

[HKEY_CLASSES_ROOT\*\shell]

[HKEY_CLASSES_ROOT\*\shell\compress with lzop]

[HKEY_CLASSES_ROOT\*\shell\compress with lzop\command]
@="\"lzop.exe\" \"-U\" \"-v\" \"%1\""

[HKEY_CLASSES_ROOT\*\shell\uncompress with lzop]

[HKEY_CLASSES_ROOT\*\shell\uncompress with lzop\command]
@="\"lzop.exe\" \"-d\" \"-v\" \"%1\""

so you just can compress/uncompress your big vmdk files just via a single mouseclick - doing it the "lzop way" is much faster than everything around.

roland

ps:
i don`t know for the moment it the lzop.exe binary from www.lzop.org is large file (>2gb) aware - but afaik there are large file aware lzop versions around.

If you're using NTFS, you can an enable compression on the individual .VMDK files (or on the containing folder).

N.B. This will almost certainly have a rather dramatic (negative) impact on VM performance.

to avoid fragmentation , it`s best to make a new folder, activate compression for that and copy the entire vm into that folder.

to "ntfs-compress" an existing large file will make look it like this on harddisk:

[c]=compressed block
[f]=free block

[c][f][c][f][c][f][c][f][c][f][c][f][c][f].......

regards
roland