I guess, it may depends on SAN disk read/write (Solaris may able to read faster compare than Linux). Try with diagnostics in your program and also check with Linux strace command.
Is there any major difference between those servers except OS flavor..like architecture, SAN connectivity...
Solaris Machine:
uname -a
SunOS ddm-app-sj-prod 5.10 Generic_142900-12 sun4u sparc SUNW,Netra-T12
Linux Machine:
uname -a
Linux sjc-lds-289 2.6.9-89.0.11.ELsmp #1 SMP Mon Aug 31 11:00:34 EDT 2009 x86_64 x86_64 x86_64 GNU/Linux
Also, perl that Linux box using is perl5.6.1 whereas Solaris is using perl5.6.0. Is that something to consider?