Question About NetBackup AIR replication

[cmwong0921]

Hi ,

Have a few question about AIR ,

1) is it possible to replicate Catalog ?

2) instead of replicate baseline copy ( 1TB ) from primary to dr site  which took very log , is it possible to copy to USB disk and paste to DR site ,so that we can reduce the replicate time for baseline copy ?

[sdo]

1) Depends what you mean.  The Hot Catalog Backups can be replicated, yes.

2) If the initial first ever baseline copy of backups is done, then subsequent AIR replications should not take so long, but this depends upon your de-dupe rates.  Yes it is possible to duplicate to a Basic Disk storage unit on USB disk, and transport the USB and then Import before duplicating again, but if your servers only have USB2, then they will be limited to c.25MB/s to 30MB/s, and so might take a long time too.  I would expect future AIR replications should be ok.

If you need more help, then we'll need to know:

3) How big the weekly full and daily incrementals backups are?

4) What the de-dupe rates your are seeing?

5) The WAN link bandwidth?

6) Some actual duration timings?

[Mark_Solutions]

A catalog AIR replication will only work if the source and target are at the same version and patch level of NetBackup - otherwise it will fail.

If you cannot put the target machine on the local network to do the first seeding for later AIR replciation then an alternative is to find some similar data on the remote site to backup .. just some similar O/S's or VMware machines .. that will often seed it wnough to get a decent dedupe database established

The local backups only need to be using a short retention period as once the AIR has run it will retain all fingerprints etc for that data

Hope this helps

[cmwong0921]

Mark,

Thanks for you reply.

Did not know that the alternate which you mentions will work beside placing the target at the local network .

[cmwong0921]

sdo,

thanks for reply .

currently at planning stage . data is 1 TB full daily , WANlink is 30mbps

do you mean i do the followings ,

1) perform first backup to msdp pool at Prod site

2) duplicate data to USB disk at prod site

3) import USB disk at DR site

4) duplicate data to msdp pool at DR site

[sdo]

That outline plan looks ok.

.

Is the 1TB in one lump/job/volume/server/disk?   Or is this from multiple backup clients?  If multiple could you not just do a few clients at a time?   I ask, because as you do more clients gradually, then there will gradually be more data to de-dupe agianst, and so after each round of implementing just a few clients then one should see better and better results.

.

Some quick calcs:

AIR	WAN link	30.0	Mb/s
	Initial full	1.0	TB
		1,024.0	GB
		1,048,576.0	MB
		8,388,608.0	Mb
	Time	279,620.3	seconds
	Time	77.7	hours
	Dedupe	80%	reduction
		209,715.2	MB
		1,677,721.6	Mb
	Time	55,924.1	seconds
	Time	15.5	hours
USB	Initial full	1,048,576.0	MB
	Speed	25.0	MB/s
	Copy to USB	41,943.0	seconds
	Copy to USB	11.7	hours

.

The USB process is going to take at least 25 hours in total, 12 hrs to duplicate to it, then you have to factor in transportion time, then a couple of hours to import, and then maybe 12+ hours to duplicate from USB to target MSDP.

And - are you allowed to ship/transport unencrypted disk?

[cmwong0921]

Hi Sdo,

Really thanks for your effort in help me on this .

There are about 12 clients, all windows server running MSSQL, exchange , Fileserver, Active directory  . I do understand what you mean by doing few client at a time .

based on 80% dedup ratio, do you mean for daily dedup replication from Prod to DR, we need 15.5 hrs  ?

I see that the USB is quite time-consuming.

There is also a daily tape-out daily from prod ( a must-have requirements ) . In real life , how long we need duplicate 1 TB of MSDP POOL to LTO6 tape ?

[sdo · Accepted solution]

5) based on 80% dedup ratio, do you mean for daily dedup replication from Prod to DR, we need 15.5 hrs  ?

You may see much better than that, maybe as high as 90% for weekly full, and 95%+ and much smaller for daily.  It all depends on the nature of the data, change rate, and how "different/new" it is each day.  The numbers I posted could be thought of as worst case.  But then they might be best case.

6) I see that the USB is quite time-consuming.

Again, maybe it will, maybe it won't.  If the server and the disk are USB3, then you may see times that are a fair bit shorter, but then the MSDP re-hydration performance may become the bottleneck.

7) There is also a daily tape-out daily from prod ( a must-have requirements ) . In real life , how long we need duplicate 1 TB of MSDP POOL to LTO6 tape ?

Depends upon re-hydration rates, i.e. depends upon several factors, but principally disk performance of the MSDP pool.

If your MSDP disk pool can sustain say a conservative 50MB/s re-hydration rate, then 1TB at 50MB/s = c.6 hours, from:

1.0	TB
1,024.0	GB
1,048,576.0	MB
50.0	MB/s
20,971.5	seconds
5.8	hours