I have several nfs servers that have had problems recently that I believe are related to software raid. Perhaps it is a known bug, perhaps I am doing things wrong... Anyway, It is a layered approach as follows xfs filesystem ontop of LVM2 ontop of software raid1 ontop of fiber channel disks. This is a debian distro. Kernel is standard 2.4.26 with patches for xfs quotas and device-mapper(for LVM2). mdadm is version 1.7.0. Fiber channel is emulex LP9802 driver version 4.30l. Anyway, a few days ago, one of our disk arrays had issues and returned I/O errors to the servers. My understanding is that software raid should mask this from the higher layers(LVM and xfs). This was not the case. xfs threw all kinds of errors and eventually needed a xfs_repair to mount back up. After things were fixed and I started the rebuild of this md, xfs began throwing I/O errors again. >From my understanding of how software raid works, if a write request to a disk fails, the kernel marks that disk as bad and continues on the good one. Looking through the kernel, read requests are round-robinned? among the disks, but if a read fails, it will retry it on the other disk(s). Is this a correct understanding? If so, then what may be causing xfs to see the hardware issues? Please advise on what I am missing here. Thanks --David Dougall - 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
