Re: [Networker] Multiple logical adv_file devices + single physical disk

It's perfectly reasonable to subdivide the filesystem into several
adv_file devices, but there are some limitations to consider:

* If you keep it to one adv_file per physical tape drive then in theory
you will not get contention between staging sessions for tape devices.

* If you write to multiple adv_file devices simultaneously on the same
filesystem, then consider the type of filesystem / disk layout
carefully. Using the correct mix here will allow you to do this without
ending up with the data being laid out inefficiently - eg fragmented,
and then being slow for staging or restores.

* Your base enabler license limits the number of devices you can have
per storage node - both adv_file and tapes...   On a single host
network_edition server for example that's only 8 devices in total.


> -----Original Message-----
> From: EMC NetWorker discussion 
> [mailto:NETWORKER AT LISTSERV.TEMPLE DOT EDU] On Behalf Of Lee Roth
> Sent: Saturday, 29 September 2007 9:55 AM
> To: NETWORKER AT LISTSERV.TEMPLE DOT EDU
> Subject: [Networker] Multiple logical adv_file devices + 
> single physical disk device?
> 
> Networker for Unix V7.4 (Solaris)
> 
> Currently, I have a 1TB disk setup that is mounted as an 
> adv_file device.
> I have a single media pool called "DiskBackup" that uses the physical
> adv_file device (e.g. mount is "/large_disk"). Backups occur 
> to disk, the
> savesets are then staged to tape based on fullness of the disk device.
> 
> Networker, of course, treats this 1TB of disk space as two 
> volumes: The
> "normal" one that it writes to and a "read-only (RO)" twin that can be
> used (in some situations) for concurrent operations.
> 
> On occasion, the RO part of the disk space gets tied up with some
> long-winded operation and isn't free for other tasks that 
> might need only
> comparatively brief read-only access.
> 
> Would doing the following be possible/good/bad... (am I insane)?:
> 
> 1) Create a one-per-client symbolic link to the physical 1TB 
> disk device, e.g
> 
>   ln -s /large_disk /client_disk/alpha
>   ln -s /large_disk /client_disk/bravo
>   ln -s /large_disk /client_disk/charlie
>   ...
> 
> 2) Create a unique media pool for each client that points to its own
> personal symbolic name:
> 
>   Pool:  backup_alpha    Target Device:  /client_disk/alpha
>   Pool:  backup_bravo    Target Device:  /client_disk/bravo
>   Pool:  backup_charlie  Target Device:  /client_disk/charlie
> 
> Make sure that each client-specific pool specified their client as the
> one-and-only client that uses that pool.
> 
> ---
> 
> My thinking is that if Networker is busy cloning client 
> "alpha" savesets
> to tape drive #1, then I could start another clone operation of client
> "bravo" savesets (to a different tape drive, media from different tape
> pool) that would not have to wait for the RO disk device to 
> first become
> free from its long-winded cloning operations with client 
> "alpha" savesets.
> 
> Obviously, if only reading is going on no real worries, but 
> would horrible
> things happen if simultaneous backups of these clients were going on?
> 
> Thanks,
> 
> -- 
> Lee Roth
> 
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Re: [Networker] Multiple logical adv_file devices + single physical disk device?
