ICRC's

[Thomas Hurst]

* Larry Rosenman (ler at lerctr.org) wrote:

> I'm getting the following on a zpool scrub:
> 
> ad8: WARNING - READ_DMA UDMA ICRC error (retrying request) LBA=54817587
> ad8: WARNING - READ_DMA UDMA ICRC error (retrying request) LBA=187521229
> ad8: WARNING - READ_DMA UDMA ICRC error (retrying request) LBA=187522189
> ad8: WARNING - READ_DMA UDMA ICRC error (retrying request) LBA=109095258
> ad8: WARNING - READ_DMA UDMA ICRC error (retrying request) LBA=101327859
> ad8: WARNING - READ_DMA UDMA ICRC error (retrying request) LBA=172911744
> ad8: WARNING - READ_DMA UDMA ICRC error (retrying request) LBA=65393370
> ad8: WARNING - READ_DMA UDMA ICRC error (retrying request) LBA=64741875
> ad8: WARNING - READ_DMA UDMA ICRC error (retrying request) LBA=262496999
> ad8: WARNING - READ_DMA UDMA ICRC error (retrying request) LBA=154593293
> 
>  	NAME        STATE     READ WRITE CKSUM
>  	    ad8     ONLINE       0     0    17

Having just experienced NTFS corruption in Windows thanks to a slightly
kinked SATA cable (hint: *never* chkdsk/fsck/etc until you're sure the
cables are fine), I would *love* to know why this causes a checksum
error at ZFS level rather than a read error that any filesystem (or
indeed RAID layer) will notice.

What's the point in having the connection protected by a CRC if it's
just going to let bogus data through anyway?

-- 
Thomas 'Freaky' Hurst
    http://hur.st/