From: Nicolas B. <nic...@ec...> - 2009-02-20 11:08:23
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Hello, I've been using UML for production servers for years, but I'm now experiencing some performance problems with UBD (I've always used it with CONFIG_BLK_DEV_UBD_SYNC). I tried to patch UBD to run several I/O threads that perform the requests in parallel. It improved performances significantly, but not enough for me. Using UML without CONFIG_BLK_DEV_UBD_SYNC improves performance a lot, but the the guest has no way to ensure that it's data is actually written on the disc. I certainly don't wan this for, e.g., a mail server, or my users will kill me. I read that there used to be some work done about using AIO for UBD, with the device file opened with O_DIRECT. As far as I can see, it lokks exactly like what I need. I read that Jeff reverted the change just before 2.6.14, but he was then saying that he would re-add it soon... What's the status of UBD with AIO nowadays? Does anyone use it? Where can I find a patch that implements this? Regards, Nicolas |