British developer Red Gate Software has released the latest version of its SQL Backup tool with new network resilience functions, self-healing log shipping and improved compression capabilities.

The Cambridge-based firm encourages interaction with its customers and the wider database admin and developer community with initiatives like its popular SQLServerCentral.com website. It says that the software's new version 6 features are a response to feedback from users who complain about continued reliance on flaky networks. If there's a hiccup on the line when they are writing backups across networks then it is nearly always a case of having to start all over again.

Colin Millerchip, RedGate's SQL Backup Pro 6 product manager, explains: "Let’s say you’ve transferred half the file across the network and then there’s a temporary outage in the network, SQL Backup will pause for a configured length of time, maybe thirty seconds, and then try again and it will do that ten times. Those are both configuration settings that you can adjust. And when it tries again, if it makes a connection, if it was just a short-term outage, it then picks up from where it’s already transferred, so if you’d already transferred half the file it then tries to transfer the remaining half."

Many DBAs use log shipping as a way of keeping a standby copy of a SQL Server instance on a separate machine, often at a disaster recovery site. Again, connection can be low-bandwidth and suffer from outages that can disrupt this process, meaning manual fixes often have to be made after the fact.

Millerchip says: "If you have a longer outage, let’s say your network goes down for an hour, what happens is your transaction logs keep getting made and they’re being stored on the source server and every time a transaction log is created we try again to transfer across the network. And if the network comes back up after, say, an hours delay, then we transfer this big backlog of transaction log files and reapply them in the right order onto your target disaster recovery server. So, even in that situation, even in a long outage, the log shipping process survives that long outage and it self heals, as it were." 

SQL Backup Pro 6 offers a new compression level which means the software’s compression analyser now lets users choose from four compression levels, depending on whether their priority is speed or size of backup.

Compression is not just a matter of saving space says Millerchip, there are time/cost benefits too. "As you put more and more data into your databases, so the maintenance window for running a backup gets longer and longer and longer and for some people it gets to the point that they can’t run a full backup in their maintenance window," he says. "By compressing the data and by the mechanisms used in our compression, you get not only a saving in disk space but you also get a saving in the amount of time taken to do the compression."

Red Gate will soon be including a new object-level recovery function in the Pro edition of SQL Backup 6 that it has taken from its SQL Compare Pro and SQL Data Compare Pro products.

Millerchip says: "If somebody accidentally deletes a table and if it was from an extremely large database what you’d typically have to do if you were just using native SQL Server is you would have to find your backup, restore the entire backup and then go and find the single table in that backup and recover that table into your production database, for example. And the problem with that is it’s a very slow process. It needs a lot of disk space and it takes a long time, so object-level recovery lets you take a backup and then just select from the backup the one object that you need."

SQL Server Backup 6 Pro costs £495 ($795) per server, with discounts for multiple licences. A fully-functional 14-day trial version is available from the Red Gate website.