Flash storage, once too expensive even for enterprise-class primary storage arrays, has gone mainstream. Today’s flash drives are highly reliable, relatively inexpensive, and they’re showing up all over the place. For example, Datto introduced the world’s first all-flash BDR device last year, the SIRIS 3 X1. Since then, we have added flash storage across the entire SIRIS product line. To better understand why, it helps to take a look back at how backup has evolved over the past decade.
Traditionally, on premises backup was all about high-throughput, high-capacity disk arrays or tape libraries. A physical server sat in front of the storage system to run the backup software, which created backups and was used to conduct file restores. Bare metal recovery typically required a separate application, and disaster recovery meant tapes stored offsite with Iron Mountain or another secondary location—if it happened at all. Offsite replication was cost prohibitive, requiring a massive technology investment. So, recovery time was slow and data loss was commonplace.
Today, the backup landscape looks considerably different, thanks in large part to snapshots and server virtualization. Image-based backup products have changed the way we think about backup and recovery completely. These solutions create a snapshot or “image” of a virtual machine (including its operating system, applications and data) on the backup device. Many systems, including Datto’s, can also replicate images offsite for disaster recovery—in our case to the Datto Cloud. This allows users to run operations from a backup instance of a virtual machine (on premises or offsite), while primary server data and applications are being restored. This approach is commonly referred to as “instant recovery” or “recovery in place.” Datto’s version of this technology is known as Instant Virtualization.
However, when you failover from a high performance server to a system that was not designed to support production workloads, bad things happen. Users immediately notice a drop in performance (if the application works at all). Datto SIRIS is designed with this in mind. It delivers the throughput that backup and restore operations require, as well as the random read performance necessary for Instant Recovery.
“Both our traditional hard drive and flash SIRIS models are powered by an impressive Xeon D CPU system, said Patrick Trofa, Hardware Product Manager. “And, flash pushes the envelope further with reliability and performance benefits. Our tests have shown flash provides significant IOPS benefits for Instant Virtualization.”
The ZFS file system on SIRIS uses two levels of memory-based caching for performance optimization of random reads. The first is DRAM based and the second is flash based. This configuration delivers latency reductions of up to 90% over traditional hard disk drives, with 5x to 10x improvement for 8K random read IOPS depending on the SIRIS configuration and data set.
Another reason flash hasn’t historically been used in backup systems has to do with drive wear. Backup is a write-heavy process, and as such, it can be taxing on SSD life. To address this, SIRIS’ ZFS file system only writes a full backup image once instead of making full copies week after week. And, it avoids the excessive wear associated with reverse incremental backups because full backups do not need to be synthesized for restore.
“You don’t need to worry about flash wear, because ZFS handles reads and writes so efficiently,” said Dan Flanigan, Director of Product Management.