Running an incremental right before a Synthetic full, on the same day, using calendar

[RLeon]

Netbackup 7.x

Hi all,

In a typical Synthetic full backup calendar schedule weekly cycle (assume the first traditional full is successful), you'd have something like:

Mon - Differential Incremental
Tue - Differential Incremental
Wed - Differential Incremental
Thu - Differential Incremental
Fri - Differential Incremental
Sat - Differential Incremental
Sun - Synthetic Full

The problem with the above is that, the Sunday file changes on the client weren't really backed up.

As the Admin guide explains:
"Since a synthetic backup does not involve direct contact with the client,
a synthetic backup is only as current as the last incremental backup.
If there is a concern to reduce a potential gap in backup coverage,
run an incremental backup before the synthetic backup."

Good advice, so what I would want to do is for the Sunday backup to become:

Mon - Differential Incremental
Tue - Differential Incremental
Wed - Differential Incremental
Thu - Differential Incremental
Fri - Differential Incremental
Sat - Differential Incremental
Sun - Differential Incremental, then Synthetic Full

What is the best way to configure the above using calendar based schedules?
I understand that the Sunday Differential Incremental schedule will NOT be run because the Netbackup schedular will only run one scheduled backup a day per client+policy, and it will pick the Synthetic Full schedule because it has a lower recurring frequency (once a week compared to once a day).

...Or does the "lower frequency = higher priority" thing not apply here?

Thanks all,

RLeon
 

[revarooo]

RLeon,

You will have 2 schedules. One for your incrementals and one for your Full Synthetic, so just schedule the incrementals for all day, then run the synthetic full on the Sunday. Now you need to ensure the incremental on Sunday has finished. So ensure the Full is outside of the Windows for the incremental.

[Andy_Welburn]

but we were utilising frequency based backups so not relevant here, per se.

Obviously, we do have to schedule in an incremental on the same day that the Synthetic Full runs, but as revaroo stated, we just ensure that the window for the incremental was prior to the full giving it enough time to run before the window for the full opens.

[RLeon]

Thank you both for your inputs.

So if I understand correctly, I could avoid the "only the low frequency schedule runs" problem by not overlapping their backup windows.
Are the following assumptions correct?

1.
Only the Synthetic schedule will run because their windows overlap, and that the Synthetic schedule has a lower recurring frequence:
  Incremental schedule Sunday window: 01:00 to 09:00
  Synthetic schedule Sunday window: 06:00 to 14:00

2.
Both schedules will run on Sunday because their windows don't overlap:
  Incremental schedule Sunday window: 01:00 to 09:00
  Synthetic schedule Sunday window: 14:00 to 18:00

But then, if "2." is true, what would happen if the Synthetic windows kicks in (14:00) when the Incremental job is still running? (Let's just assume it is a really long incremental job...)

Thanks,

RLeon

[Andy_Welburn · Accepted solution]

as the incremental window opens first, the incremental will run first!

If the incremental is still running when the synthetic window opens then the latter will wait until the former has finished - as per 'normal' backups - otherwise the synthetic will commence when it's backup window opens.

The only time where you'd have to worry about "which one runs first" would be if both backup windows opened at the same time - a while back, in instances like that, we used to stagger the window by 5 minutes "just to be sure".

[RLeon]

Am I correct in saying that for as long as the two backup windows don't start at the exact same time, both schedule backups will run on the same day?

Thanks,

RLeon

[Andy_Welburn]

one schedule running will (should) not preclude another schedule from running later if it's window is still open - altho' you've got me doubting myself now, it's been a while since I've had to deal with 'contentious' schedules!

[RLeon]

Marianne had very good article/document that explains it:
https://www-secure.symantec.com/connect/articles/netbackup-frequency-based-scheduling

As for calendar based schedules, I have been under the impression that Netbackup will always only run one schedule a day per policy+client combination, picking the schedule that runs less frequently.

I could be totally wrong with this though.
The admin guide talks a little about this, but it wasn't very clear for me.

I suppose I could test it to find out, but as always, I'm also interested in finding official references.

Thanks,

RLeon

[Andy_Welburn]

Tend to shy away from calendar apart from doing monthly backups on nth day of the month & use frequency based everywhere else - that's why I'm a little unsure of behaviour re: windows & priority, but testing now for my own sanity if nothing else (altho' I'm still of the opinion that even if calendar it will still attempt to run both incrementals & fulls on the same day if windows & resources allow).

[RLeon]

Welp, I better start doing my own test as well then.

Although revaroo was the first to give me a solid answer, I will mark Andy's post as solution based on participation.

Thank you both.

RLeon

[Andy_Welburn]

Created new policy.with 3 schedules

One Off FULL - no start window, 'seeding' backup for synthetic.
Normal Incremental - calendar based all Wednesdays 2 week retention 08:40 - 12:00
Synthetic FULL - calendar based all Wednesdays 6 week retention 08:50 - 12:00

Ran the One Off FULL as a starting point.
Incremental started at 08:40 as scheduled & ran to completion (1 minute)
Synthetic started at 08:50 as scheduled & ran to completion (5 minutes)

So that confirms that.

Maybe test next with both start windows at same time .....

[Andy_Welburn]

Policy as earlier.

No One Off FULL required.

Normal Incremental - calendar based all Wednesdays 2 week retention 09:00 - 12:00
Synthetic FULL - calendar based all Wednesdays 6 week retention 09:00 - 12:00

Incremental started at 09:03 a little later than scheduled & ran to completion (1 minute)
Synthetic started at 09:05 once incremental had finished & ran to completion (5 minutes)

Now that I'm not totally sure I expected. All things being equal, as the retention period for the Synthetic FULL is greater than that of the Incremental I expected it to be the other way around. Maybe retention not involved in this instance & merely looking at when backup last ran for each schedule & basing it on the fact that it was longer since the Incremental last ran compared to the other.

.... testing over. I'm sure you'll make a sound decision on the findings!

[RLeon]

Thanks for all your effort Andy,

Your test results will be very useful references. I suppose you are testing with version 7.5?

RLeon

[Andy_Welburn]

ROFL!!

What makes you say that? I wish!

Unfortunately I'm nearly EOL (!) with my old 6.5.6 system. We live in hope!

All joking aside, NB7.5 *should* run by the same methodology regarding job scheduling but that's not actually a given. So, if you want to test & 'update my findings' you're more than welcome!

[RLeon]

Don't worry, you have a few months left to go, enjoy it while it lasts...

I've seen discussions here about undocumented changes in job scheduling behaviors between MPs/versions. In the end I think it is all about finding out the quirks by yourself. The hard way.

RLeon