LeftHand is not only iSCSI

About a year ago, LeftHand disk array developed by the eponymous company, which HP acquired in 2008, appeared in the HP storage product portfolio.

Usually, LeftHand products are considered only as primary-class disk arrays designed for SAN storage networks based on iSCSI protocol. However, the development of LeftHand, which is now officially called the HP StorageWorks P4000 , stands out against other systems by implementing a number of advanced data protection functions, some of which until recently could only be found in high-end disk arrays.

Before talking about the advantages of the functionality of the StorageWorks P4000, it makes sense to briefly describe its architecture. The P4000 is built from storage modules (essentially a rack-mounted dual-processor HP ProLiant standard architecture server with redundant power supplies and fans), each equipped with a storage controller, two ethernet network cards with one or two optional 10-gigabit Ethernet cards, a RAID controller and, of course, hard MDL SAS disks. Storage modules are managed by a specialized SAN / iQ operating system.

Via Ethernet using the iSCSI protocol, these modules are connected into a cluster, and their resources (disks, RAM, network interfaces, cache memory) are combined into a common pool. For failover connectivity between cluster nodes, Ethernet network connections can be backed up, since, as mentioned above, each node has two network cards. In a StorageWorks P4000 cluster, you can create disk volumes that consist of drives that are physically installed in different nodes. The cluster is managed using the Centralized Management Console (CMC), which is installed on a Windows or Linux computer connected to an iSCSI SAN network.
')
So, let's see what a P4000 storage module cluster can do under SAN / iQ management with pooled resources:

• storage capacity is scaled horizontally by adding a new StorageWorks P4000 module to the cluster. This operation is performed in a hot mode and SAN / iQ automatically expands the volumes to the disks of the new module (to reduce the load on the network when changing the configuration of the volumes in SAN / iQ, the Bandwidth throttling function of traffic is used). In addition, nodes can be excluded from the cluster online;
• StorageWorks P4000 supports multi-level storage — for example, you can create a volume whose data is stored on fast and expensive SAS drives, and when this data becomes outdated, you can move it to SATA drives on another module. Moving a volume between physical disks and changing the configuration of a volume SAN / iQ performs automatically — the system administrator does not need to manually migrate data and reconfigure the volume;
• The Network RAID feature of SAN / iQ allows you to build a distributed RAID array from disks installed in different StorageWorks P4000 modules. In the first version, Network RAID only supported first-level RAID, i.e. it was possible to mirror disks of different modules among themselves, but the new version of StorageWorks P4000 G2, which was released earlier this year, already supports RAID 5 and 6, so you can provide more economical (in terms of overhead for usable capacity) data duplication . Network RAID allows you to integrate storage modules installed at different sites into a disaster-proof distributed RAID array;
• In SAN / iQ, the function of dynamic allocation of Thin Provisioning capacity is implemented, i.e. if the physical capacity allocated to that is consumed, you can give it additional disks online. Thin Provisioning reduces the cost of buying disks - the customer does not need to buy capacity for future use;
• instant cloning of Smart Clone volumes - system images are saved and then only the changes are copied, but not the data itself. Such cloning is very convenient for working with production data when developing and testing new versions of application software and loading OS servers through the SAN;
• SnapShot snapshots — make it easy to back up and restore data, including using the Remote Copy feature;

All of these functions are included in the standard configuration of StorageWorks P4000 G2 and the owners of these systems do not have to spend money to purchase software licenses (unlike buyers of older and middle class disk systems). In addition, SAN / iQ can work on any standard architecture server, so HP supplies this OS and as a separate P4000 software product VSA Software for building iSCSI storage systems on the x86 server hardware platform.

As always, we will be happy to answer your questions and hear your feedback if you have already worked with the P4000 line or LeftHand products.