Spectrum Virtualize Update 7.7.0 Part 2
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Last week while in Sweden and Denmark I posted about the new 7.7.0 Spectrum Virtualize software that was announced while I was there. Back home in New Zealand now, and got some time to fill you in on the rest of the features this new release brings to SVC, Storwize, FlashSystem V9000 and VersaStack.
iSCSI Storage Virtualization
Since the inception of SVC back in 2003, we have always supported Virtualisation of external Fibre Channel storage. When we added Fibre Channel over Ethernet (FCoE) capabilities in 2010 we added virtualizing of select FCoE attached storage. Now for the first time we are supporting select iSCSI storage attachment.
Initially any of the IBM Storwize systems can be virtualised over iSCSI, and the Dell EqualLogic products. You can use either 1Gbps or 10Gbps connections. As with all virtualised storage, more support will be added for other products in due course. You can use the supported iSCSI storage in standard, stretched and HyperSwap topologies. But note that quorum disk are not supported on iSCSI storage, so you will need either some local SAS attached disk, or Fibre Channel storage to provide quorum disk capability.
Compression with IP Replication
Spectrum Virtualize has supported native IP replication using the in built Bridgeworks AI engine to provide full bandwidth IP replication out the box. You can connect the in built 1Gbps or optional 10Gbps IP ports directly to your WAN/long distance IP network to provide full replication capability without the need for FC/IP routers.
7.7.0 adds the capability to compress data being sent over the IP replication links, thus may speed up replication change cycles (when using GlobalMirror with change volumes) and allow less use of bandwidth over the links. The software being built in, like the IP replication feature itself, means no additional hardware is required to compress data on the links.
The feature is enabled when creating the IP replication partnership and does not require any additional software licenses. i.e. does not require the Real-time Compression license. It also does not require the compression acceleration hardware, however if this is present in the system, it will be used. In testing we have not measured any degradation in normal compressed volume capability when this is used in addition - when using the compression acceleration hardware.
The in-built compresstimator functions can be used to estimate the benefits that you will see on a per volume basis. On that note, we added the in-built compresstimator function to the command line last year. 7.7.0 also adds the compresstimator functionality in the GUI interfaces.
When we introduced the current generation of SVC (DH8) and V7000 (Gen2) hardware, we offered the option to upgrade the system memory to 64GB (per node) for 128GB for each IO Group. Initially this extra memory was only for use with IBM Realtime Compression features. That is, the base 32GB per node was for system and cache usage, and the upper 32GB when installed would only be used for Compression cache.
One upgraded to 7.7.0, and in systems not using Compression, the full 64GB per node can be used for system and data cache purposes. Note that the extra 32GB is only used a read cache. The write cache size remains the same as we haven’t added more capability to the ‘dump to disk’ function. That is, in the event of input power loss in a data centre, the system will flush any write cache data to the storage inside each node. This has a finite bandwidth which dictates the available write cache space. While adding the extra memory gives much more cache space, it doesn’t increase the dump to disk bandwidth, hence the extra space is available as read cache only.
The 64GB memory is available on Storwize V5030, V7000 Gen2, SVC DH8 and FlashSystem V9000 node hardware.
Check back later this week for part 3 of the updates in 7.7.0