Date: Sun, 22 Jan 2017 07:23:17 -0800 (PST) From: "Rodney W. Grimes" <freebsd-rwg@pdx.rh.CN85.dnsmgr.net> To: tech-lists <tech-lists@zyxst.net> Cc: freebsd-arm@freebsd.org Subject: Re: how to measure microsd wear Message-ID: <201701221523.v0MFNHSb098409@pdx.rh.CN85.dnsmgr.net> In-Reply-To: <b6d3d647-bd78-b6df-02ad-97fc4f828a5d@zyxst.net>
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> On 22/01/2017 02:53, Rodney W. Grimes wrote: > > In either case the manufactures of flash devices have made it very > > clear that these things DO have a write cycle life time, and that > > your going to see a failure eventually if you write enough data to > > them. > > Hi, > > Is there a way one can see how many (or an average) number of write > cycles the cluster or device has had? In order to get a handle on when > it's likely to fail. Or to see what's been remapped and how many more it > can remap? If not on freebsd then on any OS? > > Maybe something that tests # remappable and warns when there's nothing left? > > I mean it's all fair and well the manufacturers saying it will fail on > average after so many writes, but that uncontextualised information is > useless if one cannot establish how many writes have already happened. I can tell you that some vendors implement smart like stuff using sdio CMD56, such as Envoy who says this: Envoy Data Memory SD and µSD controllers implement CMD56 support and specialized firmware to provide S.M.A.R.T. like features to systems designers. One of the biggest concerns that system designers have with NAND Flash based storage and mobile, remotely deployed hardware systems is replacing worn out SD Cards or µSD Cards. Or worse, not knowing IF the SD Card or µSD Card even needs to be replaced based on endurance estimates. The use case for all Solid State Storage has a significant impact on the life of the product. If system designers implement Envoy Data Memory SD Cards or µSD Cards they can monitor card life as part of the systems background tasks. Hardware that is connected can notify users or administrators in the event that the card begins to reach an END OF LIFE condition. Envoy Data Memory supports this feature with a S.M.A.R.T. tool available to our customers. Other vendors have similiar stuff, down side is most of this is vendor specific and only comes with a Windows tool. -- Rod Grimes rgrimes@freebsd.org
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