Can we use multiple backup software programs at the same time?
We've implemented EMC NetWorker (Legato) as a network based SQL Server backup solution. Previously we used SQL Server Backup via Ola Hallengren's scripts. Can we continue to do both or will that mess up the backup/restore chain?
Regarding the backup/restore chain being messed, yes, it might be messed if you try to take log backups on both backup tools, for example. See https://docs.microsoft.com/en-us/sql/relational-databases/backup-restore/apply-transaction-log-backups-sql-server?view=sql-server-ver15#Requirements . But if you would choose take a full backup using the copy only option in one of the tools, it would not mess the recovery chain.
Also, every backup you take have an impact on the server. It costs resources to generate the backups, so if you keep 2 different solutions, you might cause your server to suffer resource contention for a longer period increasing the maintenance window.