On Wed, 2005-06-15 at 10:34 -0500, Brian King wrote: > For scsi disks attached to an ipr adapter, the SYNCHRONIZE_CACHE command > gets sent to the disk and works just like when attached to any other > HBA. The ipr disk array devices, however, do not support the SYNC_CACHE command, > nor do they support the caching mode page, so SYNC_CACHE never gets sent. > So, the shutdown hook is needed to flush the adapter's battery backed write > cache for all attached disk arrays on system shutdown. Well, that means you have a whole lot more trouble in 2.6.12 than simply failing to flush a cache on shutdown. The barrier code now uses cache synchronization commands, so if you crash the on-disk image will not be what a journalling filesystem expects. As long as the battery keeps the information alive in the cache, I assume this corrects itself when ipr next powers up, but if you trusted this, you wouldn't be fussing about the shutdown cache flush, now would you? James - : send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
