Yes, as with tapes you may combine multiple drives to archive the capacity you need. You can configure these drives to a desire RAID level (For example RAID 5) for better data protection. Although most SATA, SCSI and Fibre-channel drives are Hot-Swappable you need also to check if the RAID controller supports hot-swap and if the Operating System can handle hot-removal of existing volumes.

VTL uses existing backup software and emulate Hard Drives access to look like a tape just much faster. The advantages are: well tested existing software, compatibility with current format, utilizing current investment. D2D is relatively new but is rapidly overcoming the traditional resistance to technology progress. All leading software companies now are supporting the D2D technology both in file base and blocks base. VTL seems to bridge between traditional Tape Only backup and random disk backup. If you heavily invested in Tape equipment and software use VTL otherwise use D2D and use your existing tape equipment to create D2D2T.

Creating multiple SATA RAID based Backup-sets (Snap-shot, in-house and offsite) is a good practice for Archiving or middle stage backup/recovery. SCSI and Fibre-Channel drives have better random access performance (not needed for sequential backup) but also have better reliability. For mission critical data, IQSS recommends having one backup-set (usually the snap-shot set) as a SCSI RAID and if using a network backup - Fibre-channel RAID. Also remember that current price ratio between SATA drives and SCSI or Fibre-channel drives is 1:5 per GB.

D2D-NAS uses files to backup Servers and Clients via the LAN. D2D-SAN uses block level Disk data via Fibre-channel or iSCSI. Generally SAN is much faster than NAS (see the next question) since the protocol handling is done by Hardware (although most current iSCSI solutions are implemented in software). However, Fibre-channel SAN require investment in switches, HBAs, cables and software. If your backup window is large enough for example you have the whole night to backup and use the LAN without interfering with other servers’ LAN traffic then D2D-NAS is fine. Remember that if you also use Tape, transferring data to the Tape is done off-network. You will need to invest in SAN if you want to significantly shrink your backup window and/or avoiding load of your servers and network.

There are many variables that determine the window-backup time: Network speed, clients (servers) speed, backup software (in server and client sides), target media speed (Tape or Disk) and capacity. Comparing only the target media speed may be misleading. In many cases the combination of media speed, backup software mode, and backup server processor power determine the actual window. If we eliminate other bottlenecks the media speed can give us ratio estimation. A typical Tape speed is between 5MB/sec and 20MB/sec. A typical NAS Speed (medium file size writes) is between 15MB/sec and 60MB/sec. A typical RAID Speed (write sequential) is between 50MB/sec and 200MB/sec. Based on these numbers the window backup time ratio between (Tape):(D2D-NAS):(D2D-DAS/SAN) is 1:3:10.

We recommend using one of the top 5 vendors. These software are well tested and will stay with us for a while. Backup is like insurance you don’t need it (and in many cases don’t test it) till you have a disaster and at that point you will pay dearly just to save your data. So don’t gamble with unknown backup software. The features of the leading software are very similar; for special feature or requirements call us for advice.

The main thing to remember (if you architect the system correctly) is that in D2D2T the tape performance should not be the bottleneck of the backup system and should not influence the backup window. That is because the backup is done to a Disk and the copy to the Tape is done offline at any time and preferably not by a production server. So the performance of read/write is less important than in the traditional direct Tape backup.

Also, since the frequent backup is done to the Disk including rotations and restores the Tape becomes an archive media usually stored offsite and therefore functions like Libraries and Autoloader are less critical.

IQSS recommends using low performance Tapes (and therefore low cost) and fit the tape capacity to your archiving requirement. If you already have a Tape drive or Library you’re probably OK; you don’t need to buy a new one (see the next question)

Yes, in most cases. IQSS uses known backup software that supports most Tape drive and libraries. If you already selected or have backup software, we’ll check for you the compatibility of your existing Tape and the backup software. Our D2D systems comes with standard SCSI LVD/SE, 68-pin. Other interfaces also available (Fibre-channel, FireWire, USB).

We’ll advise you for free. We believe that you want advice before buying a system, during installation, and when you have a problem. We are here to support you all the way. We also have surprisingly low prices; we know what to pick without paying premium for features you don’t really need. Try us!