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Re: Can MySql database store images?

From	Jerry Stuckle <jstucklex@attglobal.net>
Newsgroups	comp.databases.mysql
Subject	Re: Can MySql database store images?
Date	2011-04-25 09:09 -0400
Organization	A noiseless patient Spider
Message-ID	<ip3rpf$l7j$1@dont-email.me> (permalink)
References	(8 earlier) <kikf88-1rv.ln1@squidward.dionic.net> <ip3ijr$f0q$1@dont-email.me> <a31g88-6ii.ln1@squidward.dionic.net> <ip3la3$141$1@dont-email.me> <k76g88-rm7.ln1@squidward.dionic.net>

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On 4/25/2011 8:32 AM, Tim Watts wrote:
> Jerry Stuckle wrote:
>
>
>> It's done every day by a large number of companies.  But your figures
>> are way off - on a 10 GB network it would take about 3 hours.
>
> My figures are based on reality with real hosts and other stuff going on on
> both hosts and networks.
>

So are mine.  Large datacenters back up a lot more than that daily.

>>>>>> And what happens when you delete a file - but later need to restore it
>>>>>> from backup?
>>>>>
>>>>> You copy it from one of the previous incrementales - specifically the
>>>>> one that was triggered due to the file deletion on the source end.
>>>>>
>>>>
>>>> Ah, but you said use rsync - which does not create incrementals.
>>>> Rather, it syncs files between two systems.
>>>
>>> I suggest you top talking now and "man rsync". It does sync filesystems.
>>> It also has the option to backup (divert to another directory tree) any
>>> file that it is about to delete or update on the target. There are your
>>> incrementals. I've been running that method for 10 years - it works.
>>>
>>
>> OK, now the file gets replaced with a new one of the same name, edited
>> and deleted again.  Happens all the time.  Does it still work?
>
> Yes. Of course it does. rsync uses one of two methods to decide to
> replace/update the file on the target:
>
> 1) (Cheap) The tuple (pathname,size,mtime) is used as a key - if source and
> target don't match then the target is updated - or more precisely, the
> target is unlinked and a new copy transfered.
>
> This method is sufficient as the only way to break it is by perversly
> updating the mtime of you file to match and older version of the same size.
>
> 2) Do the above but include a checksum of the file as part of the tuple.
>

Which means even more work - and more prone to error.  And how long does 
it take to get to that point?  A lot longer than just restoring from a 
full backup.

>> And BTW - backups are nice.  But have you ever restored a disk from
>> scratch using your method, up to but not including the last 3
>> incrementals?
>>
>>>>
>>>>> You manage how many incrementals you keep by deleting the ones you
>>>>> don't want, either consolidating the incremental set to the nearest
>>>>> weekly/monthly - or your use the "every incremental looks like a full
>>>>> but virtue of hardlinks" and just delete the ones you no longer want.
>>>>> Usually in some patter like having the last 7 dailys, 4 weeklys, 12
>>>>> monthlys or whatever.
>>>>>
>>>>
>>>> And if you do need to restore the complete disk, you need to restore
>>>> from the last full backup plus all incrementals since then.
>>>
>>> Which bit of "reverse incrementals" are you having difficulty with? The
>>> last backup is always a full. You only touch the incrementals if you want
>>> an *earlier* copy of the file.
>>>
>>> Cheers
>>>
>>> Tim
>>>
>>
>> And have you ever tried a complete restore to a blank disk of all but
>> the last three incrementals?
>
> No because that has never been necessary. A full restore would be required
> for a host failure or a screwup involving massive file deletion.
>

So you really have no idea if it works or not.  But that's the purpose 
of backups - and a backup which can't do that is worthless.

> The incrementals are for users to go picking through when they make a booboo
> on a few of their own files generally.
>
> But in principle, you'd restore the backup then copy on top, in time reverse
> order, the incrementals[1].
>
> [1] Ok - this what you will get some surplus files that should not exist,
> but very few people complain of surplus files in the event of disaster
> recovery.
>


Except when they take up gigabytes of storage - and run out of disk 
space, for instance.  Of course, that's not something you have to worry 
about if you have a full backup.  You get exactly what you backed up - 
no more, no less.

> Or if you suspected this would be necessary in your world, and you don;t
> want surplus files, you would use a "cp -rl; rsync" methodology like
> rsnapshop does, that populates the incremental n-1 tree with a set of
> hardlinks to the current tree prior to running rsync. The net result is each
> "incremental" is actually a full snapshot on the day it was run. In which
> case, pick one and restore from it. This method costs inodes on the backup
> filesystem as well as directory overhead of a duplicate set of trees, but is
> not too inefficient for what it does.
>
> Cheers,
>
> Tim
>

The whole purpose of a backup is to be able to restore a disk in case of 
failure.  The ability to do a full restore is ALWAYS considered 
necessary by any qualified sysadmin - even on mainframes.

-- 
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex@attglobal.net
==================

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Can MySql database store images? "Robert Crandal" <rcranz143101@gmail.com> - 2011-04-23 23:47 -0700
  Re: Can MySql database store images? "J.O. Aho" <user@example.net> - 2011-04-24 09:23 +0200
    Re: Can MySql database store images? "Robert Crandal" <rcranz143101@gmail.com> - 2011-04-24 01:19 -0700
      Re: Can MySql database store images? "J.O. Aho" <user@example.net> - 2011-04-24 11:13 +0200
  Re: Can MySql database store images? The Natural Philosopher <tnp@invalid.invalid> - 2011-04-24 11:17 +0100
  Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-24 13:06 +0100
  Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-24 08:42 -0400
    Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-24 14:45 +0100
      Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-24 10:27 -0400
        Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-24 19:04 +0100
          Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-24 14:44 -0400
            Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-24 20:51 +0100
              Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-24 17:03 -0400
                Re: Can MySql database store images? Hans Castorp <REWYRLXHEGHO@spammotel.com> - 2011-04-24 23:18 +0200
                Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-24 19:55 -0400
                Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-25 08:30 +0100
                Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-25 06:32 -0400
                Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-25 12:04 +0100
                Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-25 07:18 -0400
                Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-25 13:32 +0100
                Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-25 09:09 -0400
                Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-25 14:17 +0100
                Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-25 19:29 -0400
                Re: Can MySql database store images? The Natural Philosopher <tnp@invalid.invalid> - 2011-04-25 12:30 +0100
                Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-25 13:59 +0100
                Re: Can MySql database store images? The Natural Philosopher <tnp@invalid.invalid> - 2011-04-25 18:10 +0100
        Re: Can MySql database store images? Norman Peelman <npeelman@cfl.rr.com> - 2011-04-24 16:40 -0400
          Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-24 17:05 -0400
            Re: Can MySql database store images? Norman Peelman <npeelman@cfl.rr.com> - 2011-04-25 02:57 -0400
              Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-25 08:59 +0100
                Re: Can MySql database store images? Norman Peelman <npeelman@cfl.rr.com> - 2011-04-25 21:41 -0400
                Re: Can MySql database store images? Norman Peelman <npeelman@cfl.rr.com> - 2011-04-26 06:20 -0400
                Re: Can MySql database store images? dougatmilmacdotcom@example.com (Doug Miller) - 2011-04-26 14:10 +0000
                Re: Can MySql database store images? Norman Peelman <npeelman@cfl.rr.com> - 2011-04-26 22:24 -0400
                Re: Can MySql database store images? The Natural Philosopher <tnp@invalid.invalid> - 2011-04-27 08:24 +0100
                Re: Can MySql database store images? Norman Peelman <npeelman@cfl.rr.com> - 2011-04-27 06:41 -0400
                Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-27 12:32 +0100
                Re: Can MySql database store images? The Natural Philosopher <tnp@invalid.invalid> - 2011-04-27 15:07 +0100
                Re: Can MySql database store images? "Peter H. Coffin" <hellsop@ninehells.com> - 2011-04-27 07:11 -0500
                Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-27 13:34 +0100
                Re: Can MySql database store images? "Peter H. Coffin" <hellsop@ninehells.com> - 2011-04-27 09:25 -0500
                Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-27 16:32 +0100
      Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-24 10:28 -0400
        Re: Can MySql database store images? Norman Peelman <npeelman@cfl.rr.com> - 2011-04-24 16:43 -0400
          Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-25 08:36 +0100
            Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-25 06:34 -0400
              Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-25 11:50 +0100
                Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-25 07:20 -0400
          Re: Can MySql database store images? The Natural Philosopher <tnp@invalid.invalid> - 2011-04-25 12:42 +0100
    Re: Can MySql database store images? Luuk <Luuk@invalid.lan> - 2011-04-24 16:27 +0200
      Re: Can MySql database store images? The Natural Philosopher <tnp@invalid.invalid> - 2011-04-24 15:38 +0100
        Re: Can MySql database store images? Luuk <Luuk@invalid.lan> - 2011-04-24 16:41 +0200
        Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-24 19:07 +0100
          Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-24 14:46 -0400
            Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-24 21:01 +0100
              Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-24 17:10 -0400
                Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-25 08:23 +0100
                Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-25 06:39 -0400
                Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-25 12:00 +0100
                Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-25 07:27 -0400
                Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-25 13:42 +0100
                Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-25 09:12 -0400
                Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-25 14:23 +0100
                Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-25 19:31 -0400
                Re: Can MySql database store images? "Mr. B-o-B" <mr.chew.baka@gmail.com> - 2011-04-25 20:30 -0500
          Re: Can MySql database store images? The Natural Philosopher <tnp@invalid.invalid> - 2011-04-25 12:21 +0100
            Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-25 13:46 +0100
      Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-24 13:23 -0400
        Re: Can MySql database store images? Luuk <Luuk@invalid.lan> - 2011-04-24 20:31 +0200
          Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-24 14:48 -0400
            Re: Can MySql database store images? Luuk <Luuk@invalid.lan> - 2011-04-24 21:11 +0200
    Re: Can MySql database store images? Axel Schwenke <axel.schwenke@gmx.de> - 2011-04-24 21:24 +0200
      Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-24 17:34 -0400
        Re: Can MySql database store images? Luuk <Luuk@invalid.lan> - 2011-04-25 12:04 +0200
          Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-25 06:40 -0400
            Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-25 11:48 +0100
              Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-25 07:28 -0400
                Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-25 13:36 +0100
                Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-25 09:17 -0400
                Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-25 14:30 +0100
                Re: Can MySql database store images? The Natural Philosopher <tnp@invalid.invalid> - 2011-04-25 18:13 +0100
                Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-25 19:37 -0400
                Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-25 19:35 -0400
    Re: Can MySql database store images? "Robert Crandal" <rcranz143101@gmail.com> - 2011-04-24 13:13 -0700
      Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-24 17:35 -0400
  Re: Can MySql database store images? Axel Schwenke <axel.schwenke@gmx.de> - 2011-04-24 21:29 +0200
    Re: Can MySql database store images? "Robert Crandal" <rcranz143101@gmail.com> - 2011-04-24 14:37 -0700
      Re: Can MySql database store images? Axel Schwenke <axel.schwenke@gmx.de> - 2011-04-25 00:41 +0200
        Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-24 20:16 -0400
          Re: Can MySql database store images? Axel Schwenke <axel.schwenke@gmx.de> - 2011-04-25 12:12 +0200
            Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-25 07:31 -0400
        Re: Can MySql database store images? Tim Watts <tw@dionic.net> - 2011-04-25 08:43 +0100
        Re: Can MySql database store images? Thomas 'PointedEars' Lahn <PointedEars@web.de> - 2011-05-01 09:59 +0200
      Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-24 20:03 -0400
    Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-24 17:39 -0400
      Re: Can MySql database store images? Axel Schwenke <axel.schwenke@gmx.de> - 2011-04-25 00:46 +0200
        Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-24 20:18 -0400
          Re: Can MySql database store images? Luuk <Luuk@invalid.lan> - 2011-04-25 12:13 +0200
            Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-25 06:43 -0400
              Re: Can MySql database store images? Luuk <Luuk@invalid.lan> - 2011-04-25 13:40 +0200
                Re: Can MySql database store images? The Natural Philosopher <tnp@invalid.invalid> - 2011-04-25 12:43 +0100
                Re: Can MySql database store images? Jerry Stuckle <jstucklex@attglobal.net> - 2011-04-25 09:19 -0400
                Re: Can MySql database store images? Luuk <Luuk@invalid.lan> - 2011-04-25 16:46 +0200

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