At 03:36 PM 11/14/2011 -0800, Greg KH wrote: >Not for USB 3.0 stuff. I would not recommend it >at all, and as proof of that, I ported 900+ >patches to the .32 kernel at one time just to get >working USB 3.0 support. Not anything I would >want a distro to do in the end nor want any user >to have to use. I believe you, no doubt. >Please try the 3.1 kernel and let us know what >happens. However, per the clear statement in the initial post, it is known to fail under 3.1.1: http://forums.gentoo.org/viewtopic.php?p=6871586#6871586 Not going to work on it till enough time has passed for a few more eyeballs to see the post and for the commercial vendors to respond. If nobody has seen it or has any ideas I can spend time working it next Sunday. It's trivial for anyone with a USB3-capable drive to attempt reproduction, and known to fail with radically different system hardware. Just run dd bs=1024k if=/dev/zero of=test oflag=direct The drive is configured with no partition table, one big LVM2 volume (no MD or LVM RAID), EXT4 file system, half full at 1.4TB. Write rate peaks around 110 million bytes- per-second. One possible factor that just occurred to me is that because the drive has no partitions and because the 3TB drive has 4K sectors, throughput may be much higher than is typically achieved. I've seen misaligned 4K blocking cut transfer rates by as much as 80%. Could easily be a firmware glitch in the enclosure USB3-to-SATA module. It translates 4K virtual sector addressing to 512 byte sector addressing--the actual drive in the enclosure is a WD30EZRSDTL or possibly a WD30EZRX. http://wdc.com/global/products/specs/?driveID=866&language=1 The other individual seeing this reproduced it with more than one smaller drive including an old 150GB Raptor drive. Perhaps his USB3 enclosure's interface module is of the same manufacture as the MyBook (i.e. a WD OEM card--seems likely as not) and is the villain in the piece. Wasn't able to determine this in the conversation. I'm itching to purchase three of Seagate's new 4TB USB3 drives (goal is a mirrored Bacula backup with one drive rotated offsite), but can't justify spending the $$ till I know it will work. A test run with an alternate USB3 enclosure would help narrow it. Unfortunately USB3 is too new to pick up something on eBay for cheap. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
