Shared host access to logical drives is controlled by host groupings, or partitions. The system comes as standard with support for four partitions which can be increased to a maximum of 64 using IBM's optional premium feature upgrades.
Premium upgrades are also available for FDE key management and Volume Copy which duplicates one logical drive to another location within the same appliance. FlashCopy snapshots provide point-in-time backups of selected logical drives and you get support for two as standard which can be increased to eight.
Remote mirroring is not supported on the older DS3000 series of appliances but this is now available allowing you to replicate appliances over their FC ports. Logical volumes can be resized on the fly whilst dynamic capacity expansion allows you to drop in more disks or expansion shelves and add them to existing logical drives.
For performance testing we started with a Broadberry CyberServe dual Xeon X5560 server running Windows Server 2008 Enterprise R2 and linked via a Brocade 8Gbps FC card. We mapped it to a dedicated volume and saw Iometer report a fast 648MB/s raw read throughput.
We then added a Dell PowerEdge R715 dual Opteron 6100 server also equipped with a Brocade 8Gbps FC card and mapped a second dedicated volume to it. With Iometer running on both systems we saw a cumulative raw read throughput of 1,280MB/s showing no contention for resources was occurring.
IBM's System Storage DS3512 delivers a fine blend of SAS-based storage features and is priced right for SMBs. We found it particularly easy to deploy in the lab, performance is excellent and the levels of redundancy and expansion options make it highly versatile.
Verdict
IBM’s System Storage DS3500 arrays are a good choice for SMBs as they can start small and scale easily with demand. Few other SAS storage array vendors can match IBM’s starting price or its support for DAS applications plus optional FC SAN or IP SAN upgrades making it very flexible. We found performance over the lab’s 8Gbps FC SAN to be excellent and the high expansion potential is made all the more impressive as the only limiting factor is the number of disk drives rather than disk shelves.
Chassis: 2U rack Storage: Supports up to twelve hot-swap 3.5in near-line SAS, SAS and FDE hard disks Controller: 1 x hot-swap controller (max. 2) Processor: 800MHz PowerPC RoC Memory: 1GB cache (upgradeable to 2GB) with BBU and 8GB SD memory card RAID: 0, 1, 3, 5, 6, 10, hot-swap and hot-standby Data ports: 2 x 6Gbps SAS, SAS expansion Network ports: 2 x Gigabit Ethernet management Power: 2 x 585W hot-plug supplies Management: IBM Storage Manager 10 Client Expansion options: Two port 6Gbps SAS, four port 8Gbps FC or four port Gigabit iSCSI host cards
