Making All-Flash 3D TLC SSD Arrays Enterprise Ready

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Good post by George Crump (thank you)

All-Flash Array Vendors are now releasing systems with 3D TLC SSDs. They claim that they have reached price parity, without data efficiency, to mainstream data center hard disk arrays. 3D TLC NAND does bring the price per GB of flash storage down considerably, but it does carry the risk of device failure and data loss. Understanding how a vendor mitigates that risk is critical to vendor selection.

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Flash Storage Prices Have a Long Way to Fall. Here’s Why.

Good post by Paul Rubens (thank you)

High-performance flash-based storage is increasingly insinuating itself into enterprise infrastructure. It’s showing up in everything from server caches and directly attached storage to hybrid arrays and fully solid state storage appliances.

But corporate storage requirements are exploding, meaning enterprises will need far more storage capacity — both flash and spinning hard disk storage — in the future.

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Today’s Storage: Same As It Ever Was

Good post by Stephen Foskett (thank you)

Data storage has always been one of the most conservative areas of enterprise IT. There is little tolerance for risk, and rightly so: Storage is persistent, long-lived, and must be absolutely reliable. Lose a server or network switch and there is the potential for service disruption or transient data corruption, but lose a storage array (and thus the data on it) and there can be serious business consequences.

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SSD Endurance. What does it mean to you?

Good post by Andrey Kudryavtsev (thank you)

I continuously think about the endurance aspect of our products, how SSD users understand it and use it for its positive benefits. Sadly, endurance is often underestimated and sometimes overestimated. I see customers buying High Endurance products for the benefit of protection, without understanding the real requirements of the application. Now that piece of night thoughts goes to my blog.

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Stop wasting your Storage Controller CPU cycles

Post by Frank Denneman (thank you)

Typically when dealing with storage performance problems, the first questions asked are what type of disks? What speed? what protocol? However your problem might be in the first port of call of your storage array, the storage controller!

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H21708 Controllers lock down during Flashcopy volume creation – IBM Servers

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Source

RETAIN tip: H21708

Symptom

On controller firmware levels 7.77, 7.83, 7.84, and 7.86, the IBM System Storage DS Storage Controller may experience an issue during a Flashcopy volume creation on a Protection Information (PI) enabled array whereby both controllers will lock down with both controllers’ seven (7)-segment LCDs displaying ‘0E’ and ‘L4’.

When this occurs, any hosts connected to the storage controller will have a loss of access.

Affected configurations

The system may be any of the following IBM servers:

  • IBM System Storage DCS3700 Storage Subsystem, type 1818, any model
  • IBM System Storage DS3512, type 1746, any model
  • IBM System Storage DS3524, type 1746, any model
  • IBM System Storage DS3950 Express, type 1814, any model
  • IBM System Storage DS5020 Disk Controller (1814-20A), any model
  • IBM System Storage DS5100 Storage Controller, type 1818, any model
  • IBM System Storage DS5300 Storage Controller, type 1818, any model

This tip is not software specific.

This tip is not option specific.

The following system firmware level(s) are affected: 7.77, 7.83, 7.84, and 7.86

The system has the symptom described above.

Solution

The fix for this issue is resolved in 7.84.50.00 and later levels and 7.86.36.00 and later levels of the controller firmware.

The files will be available by selecting the appropriate Product Group, type of System, Product name, Product machine type, and operating system on IBM Support’s Fix Central web page, at the following URL:

http://www.ibm.com/support/fixcentral/

Until the files are available on Fix Central, they can be obtained by calling IBM Technical Support.

Workaround

Do not create Flashcopy volumes on PI enabled arrays until the above mentioned fix has been installed.

Additional information

To hit the PI error, read requests must be issued that are the size of a Flashcopy repository cluster or larger. The read request must contain regions that are on the base volume and the repository volume. When the controller breaks up the read requests to the respective regions the code neglected to set a variable correctly, thus causing PI errors when the reads are sent to the drives.

See more details here