You have probably heard a lot over the past year about the growing trend toward enterprise storage consolidation. This article takes a step back and attempts to describe the meaning of storage consolidation, the key drivers leading to its adoption and some of the warning signs it may be time to consolidate your server data. We conclude with how iSCSI and iSCSI-based storage area networks (SANs) can play a part in your initial consolidation moves.
What is meant by storage consolidation?
Storage consolidation is a method of pooling disk resources so they can be managed as a single entity, and shared between servers, no matter where they reside on your network. All your storage does not have to be in one physical location. It just needs to be able to be accessed as if it were. The most common method of implementing storage consolidation is by installing SAN technology.
Why are so many companies consolidating their storage?
- The top three things most impacted by storage consolidation are:
- Disk utilization rates
- Storage management expenses
Why are some companies choosing not to consolidate?
- There are some advantages that come with staying with the standard internal disk method of building out a storage environment:
- Adding more internal disks or using external SCSI shelves is cheap
- You don't need a storage administrator
- Adding servers to add storage also increases your compute power
- Your server team is familiar with how to manage everything
While the above reasons are compelling for staying with the 'status quo' of your server environment, you can't neglect some of the warning signs that indicate it may be time to consolidate (see sidebar, "Eight warning signs you may need to consolidate your data").
After reading through these warning signs, judge for yourself whether or not the advantages of staying put outweigh the disadvantages.
Data consolidation via iSCSI-based SANs
So, how do you consolidate all your storage into a SAN and still take advantage of your investment in all the disks in all the servers you have? An iSCSI-based SAN may be a way out for you.
An iSCSI-based SAN lets you use a common Ethernet network for communication with disk drives. It can be a very cost-effective method for building out an initial, low-cost storage network.
- Below are some examples of the problems you can solve with iSCSI-based SANs:
- Tie in all your remote offices over the corporate network for backup to a central tape library in a primary data center.
- Reuse older servers by clustering them together to make highly available storage farms. Then, share out your older internal disks and shelves over the network using iSCSI software on the hosts.
- Create a SAN without buying expensive host bus adapters or SAN switches by using TCP/IP Offload Engine-capable (TOE) network cards in each server. Use your standard network switches and routers as the SAN plumbing.
- Pool older disk drives together behind an iSCSI gateway and use the older disk as a data-holding location to increase backup speeds. (This creates a two-tiered backup method. Backup to disk first to reduce the backup window, then use those disks as the source for tape backup.)
There are many more iSCSI-based solutions that can be created very cheaply. These can start you down the road toward reaping the benefits of storage consolidation.
About the author: Christopher Poelker is a storage architect at Hitachi Data Systems, a SearchStorage.com expert on storage area networks, and author of the recent book, Storage Area Networks for Dummies. Prior to Hitachi, Chris was a lead storage architect/senior systems architect for Compaq Computer, Inc., in New York. While at Compaq, Chris built the sales/service engagement model for Compaq StorageWorks, and trained most of the company's VAR's, Channel's and Compaq ES/PS contacts on StorageWorks. Chris' certifications include: MCSE, MCT (Microsoft Trainer), MASE (Compaq Master ASE Storage Architect), and A+ certified (PC Technician).
This was first published in January 2003