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Author Topic: Non-flash storage for HA server  (Read 3657 times)

dhouston

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Re: Non-flash storage for HA server
« Reply #15 on: June 23, 2014, 06:14:22 PM »

From what I have read, the write endurance of SD is actually much less than 1M.  I find it's closer to 100K.

That seems to depend on the brand and is why I said to make sure of the specs for the card you choose. Wear-leveling spreads the wear over all of the card so storage capacity remains constant but expected life is reduced as berase/write cycles increase.
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bkenobi

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Re: Non-flash storage for HA server
« Reply #16 on: June 23, 2014, 07:10:23 PM »

I just finished reading a lengthy thread on the Raspberry Pi forum:

http://www.raspberrypi.org/forums/viewtopic.php?f=63&t=19554

It has a lot of information on the actual implementation of different commands between Linux and the SD card or SSD.  It's good information, but I'm left a little confused as to what is actually implemented in the standard Raspi Debian release and how to properly set things up.  The consensus is that either SD is very robust, or it is very prone to corruption.  Very little in-between.  I think the best approach is to limit the number of needless write cycles where ever possible.  So, I'll continue to press the author to see what can be done.

With as many "experts" as were posting in that thread, I guess I'm unclear on why there isn't a consensus!   B:(

dhouston

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Re: Non-flash storage for HA server
« Reply #17 on: June 24, 2014, 02:32:50 PM »

I'll look at the thread you posted later. I've been trying to find a definitive rating for the expected life and have found everything from 10,000 to 1,000,000 erase/write cycles but have yet to find it clearly stated on any of the cards I looked at they tend to opt for years of use which likely came from marketing rather than engineering. AFAIK this is the same type of memory as used by Microchip & Atmel in their microcontrollers and, most if not all, of these have offered 1,000,000 erase/write cycles for several years.

That may soon be moot as the latest SDXC standard supports up to 2TB capacity. So far, I've only found 128GB readily available. And, they use exFAT which may not currently work with the Pi.
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