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August 3rd, 2008 18:00
Networker D2D2T backups and D2T cloning speed
Hi,
I'm in a process of evaluating a D2D2T backup architecture which uses LTO4 as tape technology, and adv_file devices for the D2D part. The outcomes are to get faster recovery (via the D2D part), and speed up the backup of many slow smaller clients via backing first to disk, then cloning to tape (the current network infrastructure can't drive LTO4 drives fast enough).
Everything is going up to the expectations so far, except the cloning....from my research so far it looks like the D2T cloning is done as single-threaded job, with one saveset cloning at a time.
That would be OK with large savesets (some are > 100GB) , but an incremental backup of a small Unix OS file system may produce a saveset only a few Kbytes. Such small savesets can't produce the steady data stream required for the LTO4 devices (shining their shoes...).
Hopefully somebody here could answer some of these questions:
* When Networker clones from adv_file device to tape, is the adv_file saveset copied as it is without looking inside what is saved, or is "restored" internally and then backed up as a saveset to the clone tape?
* Is there any workaround for the single-threaded saveset cloning? Any plans to multiplex the adv_file savesets when cloning to tape? That looks to me as a major showstopper when using faster tape technologies to clone D2D backups, as eventually these backups have to go offsite, and the vast majority of clients use tapes for that..
Regards,
--ms
I'm in a process of evaluating a D2D2T backup architecture which uses LTO4 as tape technology, and adv_file devices for the D2D part. The outcomes are to get faster recovery (via the D2D part), and speed up the backup of many slow smaller clients via backing first to disk, then cloning to tape (the current network infrastructure can't drive LTO4 drives fast enough).
Everything is going up to the expectations so far, except the cloning....from my research so far it looks like the D2T cloning is done as single-threaded job, with one saveset cloning at a time.
That would be OK with large savesets (some are > 100GB) , but an incremental backup of a small Unix OS file system may produce a saveset only a few Kbytes. Such small savesets can't produce the steady data stream required for the LTO4 devices (shining their shoes...).
Hopefully somebody here could answer some of these questions:
* When Networker clones from adv_file device to tape, is the adv_file saveset copied as it is without looking inside what is saved, or is "restored" internally and then backed up as a saveset to the clone tape?
* Is there any workaround for the single-threaded saveset cloning? Any plans to multiplex the adv_file savesets when cloning to tape? That looks to me as a major showstopper when using faster tape technologies to clone D2D backups, as eventually these backups have to go offsite, and the vast majority of clients use tapes for that..
Regards,
--ms
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ble1
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September 2nd, 2008 06:00
is the adv_file saveset copied as it is without
looking inside what is saved, or is "restored"
internally and then backed up as a saveset to the
clone tape?
It is copied as without...
saveset cloning? Any plans to multiplex the adv_file
savesets when cloning to tape? That looks to me as a
major showstopper when using faster tape technologies
to clone D2D backups, as eventually these backups
have to go offsite, and the vast majority of clients
use tapes for that..
It is not as these should be handled without any delay. Cloning by definition is not multiplexed (that is, only those from disk - from tape they still can be).