Exchange Brick Level Backup Speed Drops from MP3 to FP5

[MaineDCAdmin]

Just completed the migration from Veritas NetBackup DataCenter 4.5 MP3 to FP3 and then FP5. The Master Server is a Sun v880 running Solaris 8.0. Before patching to FP5, Exchange Mailbox backups ranged from 900 to 1400 KB/Sec. After patching to the FP track, transfer rate has dropped to 300-400 KB/Sec. As an experiment we uninstalled FP5 on one of the Exchange Servers and installed the 4.5 MP3 (Client and Exchange Agent); the transfer rate went back up. We are using Exchange 5.5 (SP4) on both Windows NT 4.0 SP6a and 2000 SP4. Toggling the single instance storage function produced no noticable changes. The "communications buffer size" has been set to 64 kilobytes. The performance degradation has been noticed with Storage Domains with both Windows and Sun Master/Media Servers. The transfer rate for Exchange DBs (in a seperate policy, with a non-overlapping start window) remains at approximately 6000 KB/Sec after migrating from MP3 to FP5.

I'm curious if others have seen this condition, and if there is a soilution.

Thank you in advance for your comments/suggestions