Hi Tejun.
I tried the patch wd.debug. I am sorry that it took so long. I assume that this was to help the wake-up problem with the MyBook drives ( I have many problems). I added this patch to 2.6.25.9 and ran the kernel and then started up my raid-1 array and did not use any cron scripts to keep the drives awake. I left the drives inactive for 30 minutes and then tried to access them. It seems ok. If this is what the patch was meant to fix, then it does seem to work. I have only tested this one time though.
I have so many other issues that I have gone back over to USB2 instead of using the sata_sil 3512 CardBus controller, because it seems to stink badly.
Other issues with 3512 controller:
1. When I write to the array, the activity lights show burst activity, i.e. the LEDs are not on constantly, but burst visibly with gaps inbetween where there is no activity. They burst many times a second, but it's enough to see that its not going at max throughput. If I read from the disk, then *sometimes* they light up constantly without going off. Does this indicate in some way, that the controller is not being utilized to it's maximum capability? Seems like the controller is capable of higher throughput, but something in the way IO happens is hindering it.
2. A shutdown/startup or a reboot can kill the array, and then when it comes back up, only one disk is in the array and I have to re-add the other one causing a re-sync. This never happens on USB2, only when using 3512 and sata_sil on CardBus controller. One thing I notice is that when shutting down, after the the final KILL processes, I see a message saying something like "md is still active" right before the PC shuts down. Is this why I am losing a disk, because md is not being shut down properly before a reset/poweroff?
3. When the drives have gone to sleep and I try to access the mounted filesystem, or if I type "fdisk -l" after 10 minutes of not accessing the array, then the activity light on the CardBus controller lights up and does not go out for 1 minute. Fdisk -l does not report back until after the activity light has gone off. The same thing happens when udev starts when booting the system.
4. If I eject the CardBus controller, after havin unmounted the raid filesystem and having stopped md, then I get a console message saying something along the lines of: **DANGER** power could not be stopped [when ejecting the controller card]. Sounds serious. Possible that I am damaging the controller when I do this.
5. IO times are very poor using eSATA CardBus 3512. I get 15MB/s vs 35MB/s on USB2 (reads using /usr/bin/time and dd where if is the device and of is /dev/null.
Seems like either the 3512 controller card I have is just crap, and/or there are serious problems with the sata_sil driver when used in combination with a CardBus controller (anyone else out there with a CardBus?) Maybe the issues do not manifest themselves as much on PCI controllers? I am trying to source a CardBus controller at the moment that uses sata_sil24 instead.
--andrew
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