In the message dated: Mon, 05 Mar 2012 11:05:28 EST,
The pithy ruminations from John Drescher on
<Re: [Bacula-users] LTO media type mixup> were:
=> On Mon, Mar 5, 2012 at 10:44 AM, Tilman Schmidt
=> <t.schm...@phoenixsoftware.de> wrote:
=> > Am 05.03.2012 15:43, schrieb Alan Brown:
=> >> On 05/03/12 14:17, Adrian Reyer wrote:
=> >
=> >>> Well, 'Media Type' is misleading. It is more a 'Media Group'. every
=> >>> medium in the same group can be requested on every SD that support that
=> >>> 'Media Group'. It doesn't actually have anything to do with the mediums
=> >>> capabilities/size.
Good explanation. I'd strongly support changing the name of the directive in
the configuration file to something like "Media Group".
=> >>
=> >> To add confusion, any given bacula drive can only support one media type.
=> >>
Yeah.... I guess it would make sense if "Media Group" was a list of supported
strings, not a single value.
In this model, sites with multiple devices (tape libraries, disk storage
arrays, etc) could use multiple media types, with each physical device being
assigned a list of media types (in a "Media Group") that the device can use.
Furthermore, the device definition in bacula-sd.conf could list properties for
each media type. For example:
Device {
Name = lto5-changer
Media Group = LTO3, LTO4, LTO5
Media Options {
LTO3 = ReadOnly
LTO4 = ReadWrite
LTO5 = ReadWrite
}
}
Device {
Name = lto4-changer
Media Group = LTO2, LTO3, LTO4
Media Options {
LTO2 = ReadOnly
LTO3 = ReadWrite
LTO4 = ReadWrite
}
}
Device {
Name = File
Media Group = localNAS, remoteNAS_for_DR
Media Options {
localNAS = ReadWrite
remoteNAS_for_DR = ReadOnly
}
}
=> >> The only way around this problem is to define extra drives for each
=> >> media type supported (ie, LTO5, LTO4 and (read-only) LTO3).
=> >
=> > What's wrong with just defining a single media type "LTO" covering all
=> > generations in use?
=> >
=>
=> The problem is that you may want to separate your volumes so bacula
=> does not want to try to write to an LTO2 tape on an LTO5 drive.
=> Remember that with LTO drives you can read 2 generations back but only
=> write 1 generation back.
When we moved to an LTO4 library, our solution to that issue was to update
the volume status on all the LTO-2 media to "Read-Only" (in the bacula
database, but this could have been done with the physical read-only tab
on each tape). Obviously, this would be a problem if we wanted to use
both the LTO3 and LTO4 libraries.
Thanks,
Mark
=>
=>
=> John
=>
=>
------------------------------------------------------------------------------
=> Try before you buy = See our experts in action!
=> The most comprehensive online learning library for Microsoft developers
=> is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3,
=> Metro Style Apps, more. Free future releases when you subscribe now!
=> http://p.sf.net/sfu/learndevnow-dev2
=> _______________________________________________
=> Bacula-users mailing list
=> Bacula-users@lists.sourceforge.net
=> https://lists.sourceforge.net/lists/listinfo/bacula-users
=>
------------------------------------------------------------------------------
Try before you buy = See our experts in action!
The most comprehensive online learning library for Microsoft developers
is just $99.99! Visual Studio, SharePoint, SQL - plus HTML5, CSS3, MVC3,
Metro Style Apps, more. Free future releases when you subscribe now!
http://p.sf.net/sfu/learndevnow-dev2
_______________________________________________
Bacula-users mailing list
Bacula-users@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/bacula-users
