Can I use disk backup without an array?
I am investigating a network-based backup system for my company. We have approximately 50 desktops that save files locally and some shared files on the Win2000 server that need backing up. My boss likes the idea of backup to disk and I do too, as it is much faster than tape. My problem is: The most effective backup system involves storage of the media off-site in case of a fire or other disaster and total hardware loss. How is this accomplished with a disk backup array?
This will depend largely on whether you are planning to implement a disk-only backup solution and what you currently have in your backup environment. Disk-to-disk backups certainly offer some advantages, such as performance, as you are pointing out. However, offsite storage can present some challenges if tape technology is not part of your infrastructure. Without tape, some form of remote data replication becomes the only way to send data off-site (disk arrays don't travel well!).
This is not necessarily an issue if you have a remote location, sufficient network bandwidth and an amount of daily backup data that can be replicated within a daily cycle. In addition, depending on your backup data retention policy, disk space can also become a bit of an issue in the case of long-term archives.
If your organization is already using tape technology as part of a backup infrastructure, it might be a good idea to combine and benefit from both technologies: Disk-to-disk backups for onsite backups and tape copies (duplicates) sent off-site for DR purposes. To date, this is still the most cost effective method for most organizations wishing to implement disk-to-disk backups unless they have very stringent recovery time objectives (which would dictate data replication).
This was first published in October 2004