Full volume restore...a small rush of data comes off tape at the start, and then a walking-dead number of hours of zero indicated activity assembling the idea of what to do with it.
None of this is particularly a surprise, other than yes, it appears a forgotten 'who cares' section of ONTAP with still, a valuable amount of customer demand for it..and Im wondering if anyone else is applying any pressure to pull this out of the early 2000s.
Yes, there are other ways to manage data protection, but as long as this is still offered, it should receive responsible attention and adapt to what was 1 CPU systems, to now well over a dozen cores to get the job done.
Not doing this a different way than NDMP..is less of a reflection on where we are WRT to the year marked on the calendar, but certain scales make it harder to spend significantly (many multiples) more on a solution that in the end..is still a MAYBE you will use it restore proposition.
Change is in the air, and how/why/value/cost/support/attention to issues like this have become top of mind again.
_________________________________Jeff MohlerTech Yahoo, Storage Architect, Principal(831)454-6712 YPAC Gold Member Twitter: @PrincipalYahoo CorpIM: Hipchat & Iris
On Monday, May 15, 2017 6:15 PM, John Stoffel john@stoffel.org wrote:
Jeffrey> Does anyone that is using NDMP for file-dense restores also Jeffrey> notice a HUGE gap in time between starting the restore, and Jeffrey> data to begin moving...with no observable load/activity Jeffrey> during that odd bizzare Phase-0 period?
I'm not too surprised actually... the NDMP is really just a wrapper around the dump/restore built into OnTap, though I admit that maybe this has changed with cDOT.
In older 7-mode, it was just a single file under /root/<vol>/ that held the index of file(s) dumped to tape at which level. So I doubt it's been improved all that much since.
Jeffrey> We can see -hours- of 0% CPU, 0KB to disk (short of CP label Jeffrey> updates to them), which challenges us in other ways because Jeffrey> it brings average dataset recover speed/times to low Jeffrey> double-digit MB/sec numbers no matter how fast tape is.
Is this before or after you select the file(s) to restore? Or are you doing a full volume restore? I wonder if it's sorting the files by tape block or something like that before starting the restore.