Falconstor has added continuous data protection (CDP) to its Virtualtape Library (VTL) software.

Customers will be able to protect data continuously while still protecting other data with a normal backup. The normal backup goes to virtual tape where it is stored as a backup file, while the continuous protection data is saved as a journal file with a different format and cannot be read by the backup software.

This should help sysadmins achieve both recovery point objectives (RPO) and recovery time objectives (RTO) that include rapid recovery, reduced data loss, and minimal downtime, in a single product.

Several companies have virtual tape products - ADIC, with its PathLight VX, and Sepaton, used by HP. The appeal is that existing tape backup software and processes (such as Veritas' or EMC/Legato products) can be used unchanged. A tape backup is often a fake tape device implemented as a disk file which needs extra disk space. Backups complete much faster, at disk speed, and restores happen at disk speed too.

Other suppliers have CDP products, Revivio and TimeSpring for example, in which data on target disks that changes has the change copied over to a CDP appliance. Microsoft's DPM does near-continuous data protection - the minimum interval is an hour. In these disk-to-disk (D2D) products the data on target disks is copied to the backup disks by new software, not the traditional backup software. Again you need extra disks to hold the CDP data.

Typically, cheap SATA arrays will be used to hold the VTL and CDP data, with a RAID scheme to protect against disk failure. So we have two different data protection models, but FalconStor is the first vendor to offer a single product combining both. Partners such as Maxan and Copan issued supportive statements. No pricing information has been made public yet however.

Customers will most likely use the CDP component to protect critical data and the VTL part to protect less vital data.

CDP could soon become mainstream. NetApp has bought a company with CDP technology and is working in the area. EMC, HDS, HP, IBM and StorageTek, the other main enterprise storage vendors, are not saying anything - yet - about it.