The purpose of this blog is to highlight key distinctions between SSDs and HDDs for IBM i servers. Also, to suggest that some IBM Enterprise POWER users may wish to consider an Express POWER server with SSDs.
Disclaimer: iSeries and AS400 are servers. IBM i is an operating system. I use them interchangeably to make it easy for folks to find this information on the web.
SSDs are faster than HDDs – just more expensive.
Even so, over the years SSDs have become less expensive and more reliable. As a result, more IBM POWER users are considering SSDs instead of HDDs for storage.
What Factors Favor SSDs Over HDDs?
For clients that want increased performance, they pick SSDs hands down.
My small-to-medium sized POWER users that can be satisfied with 6-10 SSD storage units (1.935TB – 3.48 GB), get actual batch performance increase from a range of about 1000-2000 CPW to a range of about 3500-6000 CPW. (Actual performance depends on workload.)
As you may know, an Express (Entry) IBM i POWER server, has a limitation of 10 addressable disk bays. The Express POWER server also has a limitation of 64 GB RAM memory. For about 81% of the North American IBM i users this limitation is more than satisfactory.
If I Have An Enterprise Server, Should I Consider Moving To An Express Server Instead?
In many cases, the answer is YES.
If you are OK with a limitation of 64 GB and 3.48 TB of SSD storage, the Express POWER server will be less expensive than the Enterprise.
I have had many clients that had Enterprise (P10 Software Tier) POWER servers that had less than 64 GB RAM and less than 2.5 TB of storage discover that a new Express POWER server with 10 x 387 GB SSDs was less expensive and ran 200-300% faster than their Enterprise server did.
Let me repeat myself. Over the last decade of reviewing IBM i user install studies, 81% of the IBM i users in North America use no more than 64 GB of RAM and 2.5 TB of storage. (The vast majority use 4GB – 32GB of RAM and 300 GB to 1.5 TB of storage, irrespective of P05 Express or P10 Enterprise server classification.)
So, Is That All There Is To Know About SSDs vs HDDs?
Actually, there are more factors to consider.
First, not all SSDs are the same. Some SSDs are primarily for low usage, like write once and read often.
These are NOT what you want for a production server.
Instead, you want IBM Enterprise SSDs that are designated for heavier production use.
You can check out this link that explains the difference between SSDs and HDDs in more depth:
https://www.solarwindsmsp.com/blog/ssd-vs-hdd
Clearly, there is a big difference between how SDDs and HDDs work. At some point, SSDs wear out. On the other hand, HDDs have moving parts and at some point, they break.
Curiously, under many conditions, SSDs can be more reliable than HDDs.
While SDDs can degrade over time, if you have Enterprise SSDs AND have an IBM hardware support agreement, my sense is you have little to worry about.
Second, SSDs are more expensive than HDDs.
Conclusions
If you want performance and you can get budget approval, get SSDs. Otherwise, HDDs still get the job done.
In addition, if you have a P10 Enterprise POWER server that you need to replace, look at the cost of an Express POWER server with SSDs. Chances are it will be less expensive and give you better performance.
Not sure if Solid State Drives (SSDs) or Hard Disk Drives (HDDs) are best for your next IBM i POWER Server? I’m here to help, email me at blosey@source-data.com or call me at 714-593-0387.
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