Hi, I meant sectors and not blocks. On Fri, Jun 26, 2009 at 12:56 PM, SandeepKsinha<sandeepksinha@xxxxxxxxx> wrote: > Hi Alberto, > > + * TODO: would it be better to have M1 and M2 apart, to improve the chances of > + * recovery in case of a failure? > + * > > How do you guarantee consistency in case of any lost writes? Your > checksum might hold an updated value while your data block might be > lost or written to a wrong destination? > sector in place of block. > When implementing such integrity solutions, IMO, it is always > advisable to handle such error conditions else this might lead to > issues. Since, checksums are very tightly coupled with the data and > any misleading can be quite dangerous unlike parity which can be > recovered. > > Calculate the data's CRC, and compare it to the one found in M1. If they > + * match, the reading is successful. If not, compare it to the one found in > + * M2. If they match, the reading is successful; > > Also, I hope by M1 and M2 you refer to the entry for a particular > block in the respective IMD sector. What kind of mechanism do you use > to determine which is younger? > Is it the timestamp or some generation count? > for a particular sector and not block. > I assume information is per_block_entry in the IMD sectors. Which I > don't see in your implementation? > * > + * The imd structure consists of: > + * - 16 bit CRC (CCITT) (big endian) > + * - 16 bit flags (big endian) > + * - 32 bit tag > > Correct me If I am missing something. > > On Fri, May 29, 2009 at 12:59 AM, Goswin von Brederlow<goswin-v-b@xxxxxx> wrote: >> Now I need to get a new harddisk so I can test this without risking >> live data. :) >> >> MfG >> Goswin >> -- >> To unsubscribe from this list: send the line "unsubscribe linux-raid" in >> the body of a message to majordomo@xxxxxxxxxxxxxxx >> More majordomo info at http://vger.kernel.org/majordomo-info.html >> > > > > -- > Regards, > Sandeep. > > > > > > > “To learn is to change. Education is a process that changes the learner.” > -- Regards, Sandeep. “To learn is to change. Education is a process that changes the learner.” -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
