Hello welcome back.
So let's talk about glacier ARCHIVE RETRIEVAL.
So basically you have archive files or archive data that you would like to have again or read it from
glacier for some reason.
You can retrieve parts of an archive.
So if you have an archive that includes hundreds of objects you don't have to retrieve the whole thing
unique you can retrieve only part of that.
It is very common to group multiple objects and compress them using TARP or a ZIP format before archiving
them.
So here we are talking about like how would this file include or how would this archive include a lot
of objects within it.
It is very common to do that that you either turn it or zip it the multiple files and that constitutes
the archive that you load into a glacier retrieving archives is an asynchronous job uploading archives
to Glacier.
Remember when you said that it gets uploaded to multiple facilities then this is synchronous job and
glacier will not return a success message unless it has been copied to all the different facilities
or the all different storage devices.
So synchronous for upload asynchronous for retrieval and it doesn't happen automatically you need to
submit or initiate a request for the retrieval to be initiated.
You cannot use it as counsel for archive jobs retrieval.
So basically you can initiate the restore request.
You can also like I let's say I want to the bulk and I'm going to now to restore petabytes from Glacier.
Do I just check over five minutes.
No you can't configure that.
The servers the glacier is going to have an S send you a notification when the retrieval job has complete
byte ranges.
Very important feature of glacier.
Now let's say when I grouped multiple objects in an archive before uploading that to Glacier I knew
that I have the files in a specific order.
I have tracking of that in my database the client side one that I maintain and I know which object where
and I know the size.
This starts at byte 1 and ends at byte 1000 for instance.
This one starts at 1001 and ends at five thousand four hundred fifty five.
This one starts and so on.
So I know the by strangers.
So if I wanted to have object 1 and object to only and I don't want the rest from the archive.
So after that has been moved here.
Now I want to retrieve on the object one object too so what do I do.
You can initiate a request an H TTP get request an enraged if you get request you would mention that
I need to get from byte 1 all the way to multiples of 1 megabyte.
So you can.
Here have the sizes or you can have the by ranges but you can also have the sizes and say This one is
point five in size.
This one is one point five in size.
This one is 2.5 in size makes.
I'm talking here about megabytes.
OK so if I want object on an object too I would each issue the request and say I want from one by one
to two megabytes so the end has to be either the end of the archive or multiples of one megabyte.
So you can initiate that and what would happen is Malaysia will only bring you back object 1 an object
to the byte range that you have asked for.
So this is a very important feature especially when you group a large large number of objects into one
archive and you only need to access one or two objects of these or few objects.
You don't have to copy the whole thing.
Okay so the byte range is three and glacier support ETP get request would range in each to be header
so the byte range is in the HDP header to identify a specific byte range you may want to retrieve from
glacier archive data.
Alright so this ends the archive.
The glacial archive retrieval and in the next lecture we are going to talk about the archive or glacier
costs so stay tuned and take a break now we'll see you in the next lecture.