Thread: [Aoetools-discuss] exporting a disk read only with vblade ?
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From: Paul I. <i_p...@ya...> - 2005-03-17 21:52:02
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Hi, Does AoE support read only devices ? Is is possible to export a read only device with vblade ? I know that I can mount the underlying file system read only, but this is not at device level. Thanks, Paul |
From: Ed L C. <ec...@co...> - 2005-03-18 17:45:01
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Paul Ionescu <i_p...@ya...> writes: > Hi, > > Does AoE support read only devices ? It doesn't say anything about it. It provides a way to put ATA commands on the network, but it doesn't mandate what the storage device has to do when it gets the ATA commands. > Is is possible to export a read only device with vblade ? If the vblade ignored ATA write and write-extended commands, then it would effectively be exporting the storage read only. > I know that I can mount the underlying file system read only, but this is > not at device level. Well, if you hack the vblade to make it able to export storage read only, then I'd be interested to know how specific filesystems react. I mean, are we sure that no filesystem will attempt to write to the storage if the filesystem is mounted read only? If the vblade prints a diagnostic on write attempts, then it would be clear. -- Ed L Cashin <ec...@co...> |
From: Paul I. <i_p...@ya...> - 2005-03-18 19:47:45
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On Fri, 18 Mar 2005 12:37:17 -0500, Ed L Cashin wrote: > Paul Ionescu <i_p...@ya...> writes: > >> Hi, >> >> Does AoE support read only devices ? > > It doesn't say anything about it. It provides a way to put ATA commands > on the network, but it doesn't mandate what the storage device has to do > when it gets the ATA commands. > >> Is is possible to export a read only device with vblade ? > > If the vblade ignored ATA write and write-extended commands, then it would > effectively be exporting the storage read only. I think that just ignoring the write and write-extended commands will not be enough, but we need to send back an write error. Otherwise, the system thinks that it actually wrote a file when in fact it did not. Well, I can try this to see what happens. >> I know that I can mount the underlying file system read only, but this >> is not at device level. > > Well, if you hack the vblade to make it able to export storage read only, > then I'd be interested to know how specific filesystems react. > > I mean, are we sure that no filesystem will attempt to write to the > storage if the filesystem is mounted read only? If the vblade prints a > diagnostic on write attempts, then it would be clear. Yeah, this could be done. |