Messages in this thread | | | Date | Fri, 23 Dec 2011 18:23:18 +0000 | Subject | Re: kernel Unaligned AIO/DIO on inode EXT4-fs Unaligned AIO/DIO on inode by VirtualBox; performance will be poor. | From | Simon McNair <> |
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Hi Jan, Thank you. I did a search for "virtual box block size" and came up with the link https://forums.virtualbox.org/viewtopic.php?f=6&t=25336 which happens to be just what I wanted. I would have thought that the people at Oracle would have stuck to 512kb unless you specified a different block size via command line but as a newB I'm sure there is a million reasons why (I thought for databases or SSD'd which seem to me to be a minority case).
I've gone to a load of trouble to align my hard drive partitions, and now find I need to align my VM's as well. Major headache.
Thanks again for taking time out to answer what must have seemed a silly question to you.
regards Simon
On 23 December 2011 13:00, Jan Kara <jack@suse.cz> wrote: > Hello, > > On Fri 23-12-11 09:42:08, Simon Mcnair wrote: >> Sorry for the Newb question but I can't find much clarification of >> what this means via google search. Having seen that it's a generic >> kernel error message which just happens to be caused by Virtualbox, I >> do not think that Virtualbox is the culprit ? >> >> Dec 20 09:27:24 simon-Vostro1510 kernel: [ 345.592265] EXT4-fs >> (sda5): Unaligned AIO/DIO on inode 3408273 by VirtualBox; performance >> will be poor. > ... >> >> Linux simon-Vostro1510 3.0.0-14-generic #23-Ubuntu SMP Mon Nov 21 >> 20:28:43 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux >> >> root@simon-Vostro1510:/home/simon/VirtualBox VMs/Win7 64bit# ls -lah >> -rw------- 1 simon simon 116G 2011-12-22 20:12 Win7.vmdk >> >> Anything I can do to stop this message ?, a change in virtual disk >> file from vmdk to VDI or ...something ? > Well, kernel complains that VirtualBox is doing unaligned AIO/DIO. > I suppose that it's caused by the fact that the filesystem in Win7.vmdk > image has block size smaller than 4 KB but I'm not really sure how > VirtualBox does IO. You should talk to VirtualBox guys whether you could > tune your installation somehow so that VirtualBox works more efficiently. > > Honza -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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