ASE performance slow while running Backups

Hello -We are running ASE16 SP03 PL11 on Linux. We have noticed strange performance of ASE queries while running backups. We have seen number of queries with wait event : waiting for regular buffer read to complete. A query normally runs in few seconds ran for ove 20 minutes. When backups completed performance rerturned to what we nomally would see The extended waits for for buffer read to complete dropped down. I am wondering what can I look at . SHould I look at dump configuration ? We are dumping a number of databases, up to 5 at same time. Shared memory config for dumos is 2048 M Service threads set to 100.