On 02/05/12 00:18, Martin wrote: > How well suited is btrfs to low-end and high-end FLASH devices? > > > Paraphrasing from a thread elsewhere: > > FLASH can be categorised into two classes, which have extremely > different characteristics: > > (a) the low-end (USB, SDHC, CF, cheap ATA SSD);
A good FYI detailing low-end FLASH devices is given on: Flash memory card design https://wiki.linaro.org/WorkingGroups/Kernel/Projects/FlashCardSurvey For those examples, it looks like write chunks of 32kBytes or more may well be a good idea... > and (b) the high-end (SAS, PCIe, NAS, expensive ATA SSD). > > > My own experience is that the low end (a) can have erase blocks as large > as 4MBytes or more and they are easily worn out to failure. I've no idea > what their page sizes might be nor what boundaries their wear levelling > (if any) operate on. > > Their normal mode of operation is to use a "FAT32" filesystem and to be > filled up linearly with large files. I guess the more scattered layout > of extN is non-too sympathetic to their normal operation. > > > The high-end (b) may well have 4kByte pages or smaller but they will > typically operate with multiple page chunks that are much larger, where > 16kBytes appear to be the optimum performance size for the devices I've > seen so far. > > > How well does btrfs fit in with the features for those two categories? Regards, Martin -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
