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Recovering indexes?

Posted by George Sinclair - NOAA Federal 
George Sinclair - NOAA Federal
Recovering indexes?
September 28, 2017 03:59PM
Hi,

I don't have to actually do this as an emergency (all is well), just
asking for testing purposes.

Following a disaster recovery (on Linux) of the media database and
resource database:

1. Is there a straightforward way to recover the most recent version of
each client index (20 total) from tape?

Note: We're assuming that the media database contains all the necessary
information.

Would it simply be nsrck -L7 client1 client2 ... client20

and that's it? Or maybe just loop it?

2. I assume if you don't specify a time value then it will default to
the most recent version?

3. If you have a clone copy of each index then how can you force the
index recovery to use the clone volume?

Clearly, unlike recover, nsrck doesn't accept an ssid/cloneid argument,
and the nsavetime
values will be identical. When recovering non-index save sets, I've seen
cases wherein even
changing the mode (nsrmm -o) of the original ssid to 'offsite', and
having the clone volume
nearline, isn't always good enough. Sometimes it still requests the
original, and you have to change
the mode of the original ssid/cloneid to suspect to force it to use the
clone and then back to
notsuspect when finished. Does this technique work with nsrck -L7?

4. I assume that if your versions (possibly clone copies) are not all on
the same tape then it will automatically
find those, assuming you want the most recent version? But if instead,
you want an older version for some
clients, and the newest version for others, then you will have to
specify the time value (e.g. nsavetime) for
each one respectively, running nsrck -L7 separately for each. That right?

5. Is it recommended to run nsrck -L6 after recovering an index?

6. Will the recovered index have the same file names, time stamps,
sizes, etc., recursively as before?
In other words, if you created a manifest (all file attributes,
including sha256 hash, for each constituent file)
for a given index, would the recovered copy match that listing, or would
you expect some differences?
Nominally, change of status time (as opposed to modtime) would certainly
change.

What about after running nsrck -L6?

Thanks.

--
George Sinclair
Voice: (301) 713-4921
- The preceding message is personal and does not reflect any official or unofficial position of the United States Department of Commerce -
- Any opinions expressed in this message are NOT those of the US Govt. -


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Dag Nygren
Re: Recovering indexes?
September 29, 2017 05:59AM
On Thursday 28 September 2017 18:26:09 George Sinclair - NOAA Federal wrote:

> 1. Is there a straightforward way to recover the most recent version of
> each client index (20 total) from tape?
>
> Note: We're assuming that the media database contains all the necessary
> information.
>
> Would it simply be nsrck -L7 client1 client2 ... client20

Yes, or if youd need all clients just "nsrck -L7"

> 2. I assume if you don't specify a time value then it will default to
> the most recent version?

Yes

> 3. If you have a clone copy of each index then how can you force the
> index recovery to use the clone volume?

Depends on your Networker version:

If you have them on AFTD or DD, just make sure it is mounted and it
works for versions > 8.x
For older setups you will have to mark the original volumes as
suspect. It is a pretty standard file recovery after all. Remember
that the index files are flat files only.

> 4. I assume that if your versions (possibly clone copies) are not all on
> the same tape then it will automatically
> find those, assuming you want the most recent version? But if instead,
> you want an older version for some
> clients, and the newest version for others, then you will have to
> specify the time value (e.g. nsavetime) for
> each one respectively, running nsrck -L7 separately for each. That right?

Yes

> 5. Is it recommended to run nsrck -L6 after recovering an index?

Not needed. What is needed to pick up the new files will
be auto-run for you.

> 6. Will the recovered index have the same file names, time stamps,
> sizes, etc., recursively as before?
> In other words, if you created a manifest (all file attributes,
> including sha256 hash, for each constituent file)
> for a given index, would the recovered copy match that listing, or would
> you expect some differences?
> Nominally, change of status time (as opposed to modtime) would certainly
> change.

Probably but not 100% sure


Best
Dag


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George Sinclair - NOAA Federal
Re: Recovering indexes?
September 29, 2017 03:59PM
On 2017-09-29 08:30, Dag Nygren wrote:
> On Thursday 28 September 2017 18:26:09 George Sinclair - NOAA Federal wrote:
Thanks much, Dag :). I have some more questions on indexes, but I'll
submit that as a separate post.
>> 1. Is there a straightforward way to recover the most recent version of
>> each client index (20 total) from tape?
>>
>> Note: We're assuming that the media database contains all the necessary
>> information.
>>
>> Would it simply be nsrck -L7 client1 client2 ... client20
> Yes, or if youd need all clients just "nsrck -L7"
>
>> 2. I assume if you don't specify a time value then it will default to
>> the most recent version?
> Yes
>
>> 3. If you have a clone copy of each index then how can you force the
>> index recovery to use the clone volume?
> Depends on your Networker version:
>
> If you have them on AFTD or DD, just make sure it is mounted and it
> works for versions > 8.x
> For older setups you will have to mark the original volumes as
> suspect. It is a pretty standard file recovery after all. Remember
> that the index files are flat files only.
>
>> 4. I assume that if your versions (possibly clone copies) are not all on
>> the same tape then it will automatically
>> find those, assuming you want the most recent version? But if instead,
>> you want an older version for some
>> clients, and the newest version for others, then you will have to
>> specify the time value (e.g. nsavetime) for
>> each one respectively, running nsrck -L7 separately for each. That right?
> Yes
>
>> 5. Is it recommended to run nsrck -L6 after recovering an index?
> Not needed. What is needed to pick up the new files will
> be auto-run for you.
>
>> 6. Will the recovered index have the same file names, time stamps,
>> sizes, etc., recursively as before?
>> In other words, if you created a manifest (all file attributes,
>> including sha256 hash, for each constituent file)
>> for a given index, would the recovered copy match that listing, or would
>> you expect some differences?
>> Nominally, change of status time (as opposed to modtime) would certainly
>> change.
> Probably but not 100% sure
>
>
> Best
> Dag
>


--
George Sinclair
Voice: (301) 713-4921
- The preceding message is personal and does not reflect any official or unofficial position of the United States Department of Commerce -
- Any opinions expressed in this message are NOT those of the US Govt. -


--
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