Hi, I have a few questions about disk cache synchronization. I'm running a setup with several SATA drives (seagate ST3500630AS), installed in hot-swap bays. The host controller is an Intel ICH8 running in AHCI mode, if that makes any difference. Also my kernel is from kernel.org, version 2.6.20.12. When hot-removing a drive, I get messages such as: Jun 1 23:48:50 server kernel: ata3.00: detaching (SCSI 2:0:0:0) Jun 1 23:48:50 server kernel: Synchronizing SCSI cache for disk sdb: Jun 1 23:48:50 server kernel: FAILED Jun 1 23:48:50 server kernel: status = 0, message = 00, host = 4, driver = 00 Jun 1 23:50:22 server kernel: <3>ata3: exception Emask 0x10 SAct 0x0 SErr 0x4050002 action 0x2 frozen When the drive is plugged it mentions about caching: Jun 1 23:50:32 server kernel: SCSI device sdb: write cache: enabled, read cache: enabled, doesn't support DPO or FUA. I tried to google for more information about caching but could not come out with much. Mainly I found http://linux-ata.org/shutdown.html but this only talks about server poweron/down and suspend operations, not hotswap issues. I'm a bit confused about this caching and have two questions: * Is there anything one needs to know before hot-removing a drive ? Maybe a file under /sys that asks the drive to flush its cache ? * Does the kernel issue such cache flushing commands when executing sync() or umount() operations ? Please CC me in replies - I have subscribed to the list but did not get the majordomo confirmation message yet so who knows if that worked :) Thanks, -- Michel "Walken" Lespinasse "Bill Gates is a monocle and a Persian cat away from being the villain in a James Bond movie." -- Dennis Miller - To unsubscribe from this list: send the line "unsubscribe linux-ide" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
