The answer to your question is "It Depends" but I'll try to give to enough information so you can decide.
When backing up to tape, you must take into account that tapes are much slower than disk drives, this means that the BACKUP/VERIFY/RESTORE will be slow, and if there is a lot of data (terabytes) that can take many hours. You can use the native sql server method to achieve this or use some kind of 3rd party software like Idera/Redgate/CommVault/etc.
The other option is to backup to a local disk, for example: cheap SAN or a different Raid array. The key here is DIFFERENT!
What you do is use the native sql server method to backup to the dedicated backup partition/lun/raid set/drive ensure you have enough storage so you can rotate the backup files.
The key is to have enough free space for N+1 days you want to keep locally. Then you setup your tape backup to backup these files to tape.
The main advantage here is that the backup job runs quicker, meaning it runs for less time on you SQL Server, and since the backups are on a different storage than your SQL data and log files (MDF, NDF, LDF) files, the impact on SQL Server is virtually nothing and is a non issue.
Another important advantage is that you have the latest backup at hand and ready for a restore, that restore will be a lot faster than restoring from tape, minimizing downtime in such an event.
The way I would set it up is with the second method.
- Perform a daily FULL backup.
- Perform hourly transaction log backups
- Remove old backup files older than 24 or 25 hours.
- Perform a daily backup to tape of the location where you stored the SQL backups.
If using transaction logs, make sure your recovery models set to FULL.
If you have SQL enterprise you can even compress the backups so they take less storage space.
If not, there are 3rd party tools that can compress it for you from vendors like Idera or Red-Gate.
There is also a great open source project which I use named MSSQLCOMPRESSED
I hope this answers your question.