4 ms·
What’s the bit error rate on a card like this? Does anyone know how long 1TB of data would actually last, with zero bit flips, in a drawer? Presumably the prima
by gubby 7y ago
What’s the bit error rate on a card like this? Does anyone know how long 1TB of data would actually last, with zero bit flips, in a drawer? Presumably the primary market is JPG/MPG capture, where a few flipped bits don’t matter.
- nostalgk 7y agoAnecdotal, but I have never found SD cards to be a resilient form of storage. I frequently back up any important data from SD cards, which is a nightmare considering the sluggish read and write speeds, because I have encountered many instances of corrupted data. My use case is generally portable gaming and older digital cameras, YMMV. Main brand I used was SanDisk, however.
- pkaye 7y agoThere is a reason they don't mention the retention spec.
- monocasa 7y agoAll of the major brands are crap if you really care that much about the data on the card. I've seen major brands fail even in RO. You want an "industrial" SD card if you have a hard need of recovering the data.
- mikepurvis 7y agoIsn't it usually a RAID-1 config of 2-3 cards in any situation that actually matters? Thinking of high end cameras, boot drives for VM hosts, etc: http://www.running-system.com/microsd-card-raid-1-vmware-esxi-boot-device/ http://www.running-system.com/microsd-card-raid-1-vmware-esx... https://www.howtogeek.com/392378/what%E2%80%99s-the-big-deal-about-dual-storage-card-slots-for-cameras/ https://www.howtogeek.com/392378/what%E2%80%99s-the-big-deal...
- monocasa 7y agoI've seen controller bugs that'll take out all 3 cards if given the same access pattern.
- mikepurvis 7y agoHow likely is that if you have cards from different vendors?
- monocasa 7y agoAre you shipping a product or dealing with a fleet? You don't want two different items on your BoM just because you don't trust the vendor to actually ship a usable product.
- TickleSteve 7y agoAll FLASH devices have an erase limit before the sector becomes non-eraseable, likely it was not a bad controller but bad choice of filesystem or bad application behaviour that was causing excessive wear in a small location.
- monocasa 7y agoWith the right access pattern we could hit it at 80kb/sec distributed writes for six hours on an SD card with a wear leveling FTL, which shouldn't be possible. We confirmed with the vendor that it was a controller bug where the FTL was losing track of a virt to physical sector mapping. Also Flash isn't an acronym and shouldn't be capitalized like that.
- TickleSteve 7y agoindustrial grade SD cards have bad-block-management and wear levelling, commercial ones don't, hence their bad reputation. They also cost more due to over-provisioning for the above features.