Hi Andrew, Andrew Klaassen wrote:
During boot, mdadm starts the array before one of the two fibre-channel cards has started its disk detection. The array comes up, but with only 28 of 56 drives, and I have to manually re-add the drives and cross my fingers that nothing will go wrong during the 10-hour rebuild.
Have you considered enabling a write-intent bitmap on your array? This way, at least your rebuild will take seconds instead of 10 hours. Write intent bitmap support for RAID10 was introduced in 2005, and hopefully CentOS 5.2 supports it.
Is there any way to tell mdadm to wait longer, or to not attempt to start the array if not all devices are present, or... (any other solution you can think of)?
We have iscsi targets for drives in our array, and we make sure that we've logged into all 30 of our drives before we continue to enable mdadm (we literally count the number of iscsi sessions open). You can try counting the number of block devices present (in /dev/block) that match a certain pattern, or perhaps your fiber channel driver offers an even more convenient facility in /dev.
However, it would be great if there really was a way to tell mdadm to wait until the devices are ready. I'm not aware of one though.
Cheers! Iordan -- 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
