Does eMMC module have a reliable wear leveling system?

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Does eMMC module have a reliable wear leveling system?

Unread postby farta » Tue Aug 19, 2014 3:49 pm

I want to use a odroid-XU+E with 64GB eMMC as an personal server for svn/http/etc and for downloading as well. I don't want to add an external usb hdd. So I need to know if there is a reliable wear leveling inside eMMC to make it withstand repeated writing to the same group of files (this scenario occors especially when I submitting to svn server or doing BT downloading). Does anyone have idea about the eMMC's tec details?

The eMMC I'm about to use is this one. I'm about to install Ubuntu.
http://www.hardkernel.com/main/products ... 7454809984

Any help is greatly appreciated.
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Re: Does eMMC module have a reliable wear leveling system?

Unread postby odroid » Tue Aug 19, 2014 5:19 pm

According to the eMMC vendor(Toshiba),
Integrated MMCA Ver. 4.51 or Ver. 5.0 controller handles essential functions, error correction code (ECC), bad block management, wear-leveling, garbage collection, Logical-to-Physical Address Translation and driver software.

Reference Source
https://www.toshiba.com/taec/Catalog/Line.do?familyid=7&lineid=900195
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Re: Does eMMC module have a reliable wear leveling system?

Unread postby farta » Wed Aug 20, 2014 11:21 am

Thanks a lot odroid.
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Re: Does eMMC module have a reliable wear leveling system?

Unread postby mad_ady » Thu Oct 01, 2015 1:34 pm

Sorry for reviving this thread (and also thanks for the info). I also want to use the emmc for frequent localized writes (rrd databases from cacti/munin). Do you have any feedback about how many writes we can do on the emmc (from its spec or user feedback)? Also, do we need to do periodic trims?

Your link no longer points to their spec :(
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Re: Does eMMC module have a reliable wear leveling system?

Unread postby odroid » Thu Oct 01, 2015 1:41 pm

AFAIK, there is no flash storage manufacturer gives any number of write/erase counts guaranteed. :(
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Re: Does eMMC module have a reliable wear leveling system?

Unread postby mad_ady » Thu Oct 01, 2015 2:26 pm

Thanks. I'll report back in a couple of years, then :)
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Re: Does eMMC module have a reliable wear leveling system?

Unread postby DoubleHP » Tue Oct 10, 2017 1:26 am

I was using SDHC cards on rPi, and I am tired of burning cards every 6 months. So, I was advised to buy MMC, but I wanted to be sure they are better than SD. And I found this page.

@ mad_ady the original link is dead, but webarchive is not:
https://web.archive.org/web/20140805113 ... eid=900195
and it still states the same phrase:
e-MMC products integrates NAND flash memory and a controller chip in a single package to perform error corrections, wear leveling and bad-block

So, in emergency, I have bought an eMMC card plus the micro SD adapter on Amazon. Now, I am still looking for wear leveling in SD cards. For now, I have found various contradictory peaces of information. For SD and SDHC, each manufacturer was free to do any mess; it's said (but I have not found any proof yet) that SDXC implies WL.

This item states it can do WL:
Delkin Devices 32 GB MicroSDHC 660X UHS-I U3 Memory Card
https://www.amazon.co.uk/gp/product/B00NQX1F6G
(SDHC UHS-1 U3)

@ odroid ... wrong. Sandisk now does:
https://www.sandisk.fr/oem-design/indus ... rial-cards
Sandisk Industrial are given for 192TB written ...

Out of those OEM-industrial cards (which are not supported by the official chat room), using any standard end user Sandisk card ( https://www.sandisk.fr/home/memory-cards ) in an rPi breaks the waranty. Still, for booting an rPi, they recommend the High Endurance stream (which is also called video surveillance https://www.sandisk.fr/home/memory-card ... ce-microsd ). Both are SDXC white-white; but the industrial has the word industrial written on it.

I was said that eMMC probably includes a better WL algorythm than any micro SD card. I can't proof check it.
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Re: Does eMMC module have a reliable wear leveling system?

Unread postby odroid » Tue Oct 10, 2017 2:02 pm

Our red eMMC module for XU4 board is based on Sandisk 7250 series.
https://www.sandisk.com/content/dam/san ... ial-PB.pdf
High endurance: up to 3K P/E cycles in MLC

If you choose an MLC(x2bit) NAND based SD-card, it will give you a very similar reliability.
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Re: Does eMMC module have a reliable wear leveling system?

Unread postby mad_ady » Tue Oct 10, 2017 6:55 pm

mad_ady wrote:Thanks. I'll report back in a couple of years, then :)
Oh my, it's been a couple of years already. Time to report. So far I haven't had any problems with the emmc. I've only had one red emmc die most likely by electrical shock (it got very hot)
On one emmc I update rrds every 5 minutes, so it writes frequently in the same files.
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Re: Does eMMC module have a reliable wear leveling system?

Unread postby odroid » Tue Oct 10, 2017 7:59 pm

Yeah~ Time is flying. :D
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Re: Does eMMC module have a reliable wear leveling system?

Unread postby DoubleHP » Wed Nov 15, 2017 1:22 am

Would you have a reference for an eMMC under micro SD form, or, an eMMC card with uSD adapter for an rPi user ? https://www.amazon.fr/gp/product/B01DNV ... V087&psc=1 is out of stock ATM ...
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Re: Does eMMC module have a reliable wear leveling system?

Unread postby mad_ady » Wed Nov 15, 2017 3:47 am

You can probably use the black emmc + usd adapter with the rpi, but I haven't tried it (don't have a pi)
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Re: Does eMMC module have a reliable wear leveling system?

Unread postby DoubleHP » Wed Nov 15, 2017 4:50 am

mad_ady I have bought one last month, and it works fine; but they are now out of stock, and I don't know where to buy new ones.
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Re: Does eMMC module have a reliable wear leveling system?

Unread postby mad_ady » Wed Nov 15, 2017 5:30 am

Oh. For your needs you can probably use yellow or red emmcs as well.
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