Sybase IQ cannot drop old versions of tables while any user on any server might be in a transaction that might need the old versions. Sybase IQ may therefore consume a very large amount of disk space when table updates and queries occur simultaneously in a multiplex database. The amount of space consumed depends on the nature of the data and indexes and the update rate.
You can free disk blocks by allowing the write server to drop obsolete versions no longer required by queries. All users on all servers should commit their current transactions periodically to allow recovery of old table versions. The servers may stay up and are fully available. The dbremote processes must all continue to run to forward the latest information about the use of table versions on each query server to the write server.