Restoreing Dump on FreeBSD headless server
bsd
bsd at todoo.biz
Mon Jan 4 22:03:44 UTC 2010
Le 4 janv. 2010 à 22:36, Jerry McAllister a écrit :
> On Mon, Jan 04, 2010 at 08:42:33PM +0100, bsd wrote:
>
>>
>> Le 4 janv. 2010 à 19:56, Jerry McAllister a écrit :
>>
>>> On Mon, Jan 04, 2010 at 07:08:51PM +0100, bsd wrote:
>>>
>>>> Hello folks,
>>>>
>>>>
>>>> I would like to know how to proceed in order to restore a dump from a
>>>> backup headless server (remotely using ssh).
>>>
>>>> How am I supposed to proceed, should I first install the server (a FreeBSD
>>>> Fresh install with spare partition) then restore the dump on an empty
>>>> partition ?
>>>
>>> Depends on what you have and what you want to restore.
>>> Is the reason for the restore because the old disk went belly up?
>>> Or did you just nuke some stuff accidently. Is the restore the
>>> boot disk or an extra work disk?
>>
>> Well, to tell you the truth: I am using a remote backup solution since 2.5
>> years and the provider has just told me that he would no longer support
>> my hardware so I need to rebuild a new server based on my previous config
>
> I am not clear on what you mean by a 'remote backup solution' - do you
> mean that you are using dump(8) but writing to some remote device or
> do you mean you are using some '3rd party' backup software/hardware
> that your provider/hoster is supplying?
I am using dump(8).
I have successfully created a backup of all major partition of my server which is now secured on a remote HD.
>
>
>>> In the first case, yes you will need to create something on the disk -
>>> some sort of filesystem. Probably that would mean using a fixit
>>> image to boot and do an fdisk(8), bsdlabel(8) and newfs(8).
>>
>
>> Ok, I think the server I will install that on might use some sort of
>> virtual KVM that could allow me to do that
>
> Well, that could be helpful. It should give you a console type access
> which is convenient in installation situations. Does that 'KVM'
> supply the backup device too, or talk to it directly?
I haven't tried It so I don't know what functionnality It offers…
But I guess I might start a fresh install from that console…
At which point should I do the restore(8) in the install process ?
>
>>>
>>> It the second case, the filesystem[s] is[are] still intact and you
>>> only need to do an 'interactive' restore of just the files you want.
>>> IF you are doing an intereactive restore and if you have room, it may
>>> be easiest to copy the whole dump file over to some big space on the
>>> system and run the restore from that copy. Then you can just ssh in
>>> and run it just as if it was setting beside you.
>>>
>>> The same might not be true if you are replacing a destroyed disk
>>> because the restore will be a complete one and no file selecting
>>> will be necessary.
>>>
>>> If you cannot get physical contact with the machine, and the disk was
>>> damaged and replaced, you may have to learn how to do a network boot
>>> and install. I have never had to do that so am not a good one to guide
>>> that process.
>>
>
>> Well my idea was to rebuild the new server based on the dump I have
>> realised (in order to save me the time to do the reinstall).
>> But from what you are telling me It might not be so easy
>
> I am not clear again just what you are meaning by 'based on the dump
> I have realised'. Do you mean that you would keep the filesystem
> structure you have already? IS there a dump file/tape for each
> filesystem in the old system?
Dump is stored on a remote HD.
There is one dump file per partition (not for /tmp).
>
> If that is what you mean, good. There is no harm in keeping the
> old filesystem structure if it was working for you. Take a look
> at how much is used in each filesystem and think if you need to
> change the size. But, that is just a detail of sizing the partitions
> and not a critical structure consideration. If the new system has
> larger disk, then you can make use of it just by making bigger
> partitions where they are needed.
Ok.
>
>
>>>
>>> In either case of having to create slices, partitions and filesystems,
>>> you do not have to do a complete system install. You need to do just
>>> enough building to have the filesystems created and mountable.
>>
>> Yes but how should I partition that ?
>>
>> Should I re-create the
>>
>> /
>> /var
>> /usr
>> /tmp
>>
>> or
>>
>> / with minimal system
>>
>> and re-create the mapping with nothing on slice.
>
> Create what you want it to be and go from there unless the old and
> the new structure are incompatible in some way. My usual set of
> partitions/filesystems are:
>
> /
> swap
> /tmp
> /usr
> /var
> /home or other convenient name such as /bighome
> /work if there is a lot of extra space on the new disk and
> you don't want it clumped in with the rest for some reason.
> I usually put all the rest in that /bighome filesystem.
> If I have an extra disk with lots of space, I make that /work
>
>
> But, if your structure is working for you, stick with it.
>
>>
>>
>>> The fixit
>>> is just fine for that. If you can get that going remotely, then
>>> do the fdisk, bsdlabel and newfs-s from that and then restore from
>>> the dump to the new filesystems.
>>
>> Ok, that should be the good path
>>
>
> Yes, unless you are changing the structure (not size, but organization
> of the filesystems) just make the partitions and newfs them and resture
> the dumps to them.
>
>>
>>> Forget about doing a real install.
>>>
>>>>
>>>> Should the new empty partition be the exact same size as the dumped
>>>> partition ?
>>>
>>> It just has to be large enough to hold what you restore.
>>> In fact, it is a good time to increase or adjust filesystem sizes if
>>> you have more room on the replacement disk.
>>
>> Good
>>
>
> That is the advantage of using dump/restore for your backups. It is
> agnostic to the size of the partition as long as there is enough room
> to hold things. Something like dd(1) which is great for some things
> forces you to stick with the exact sector complement and so isn't
> really a good backup tool.
>
> One thing to consider, if you are copying from an old machine
> to a new one is to create the slice/partitions/filesystems and
> then use rsync to move the files from the old machine to the
> new one. It is quite efficient if both machines are available
> to be running at the same time. But, if you have to work from a
> backup file or tape somewhere, then that is not a good option.
Ok Thank you very much Jerry.
As both filesystem are going to be up and running at the same time, I guess It will be quite easy to do this operation…
Even if I have to crash couple of system on the new machine, that shouldn't be a problem -- after all It is by experimenting that we all progress!
I'll maybe do a follow-up on the thread if I have problem somewhere during the operation (It shouldn't take place until one week)…
Thanks.
>
> ////jerry
>
>
>
>>>
>>>>
>>>> Is there a tool that could allow me to restore remotely ?
>>>>
>>>
>>> You can use rsh(1). I have done that.
>>> Probably some specific ssh method too, but I am so old I haven't
>>> done one with that new fangled secure ssh yet...
>>
>> Ok.
>>
>>
>> Thanks.
>>
>>>
>>> ////jerry
>>>
>>>
>>>>
>>>> Any advice or howto will be (very) welcome.
>>>>
>>>>
>>>> Thanks.
>>>>
>>>>
>>>> P.S. Happy new BSD year !!
>>>>
>>>>
>>>> ¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯¯
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>>>> bsd @at@ todoo.biz
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>>>>
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>>
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>> Gregober ---> PGP ID --> 0x1BA3C2FD
>> bsd @at@ todoo.biz
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>>
>> P "Please consider your environmental responsibility before printing this e-mail"
>>
>>
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Gregober ---> PGP ID --> 0x1BA3C2FD
bsd @at@ todoo.biz
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