Re: 1.5TB drives due in August!

Discussion in 'NZ Computing' started by Lawrence D'Oliveiro, Jul 14, 2008.

  1. In message <48785eae$>, thing wrote:

    > get 2 and raid1 it...and dont back up...


    Or get 2, put the second one in an older machine, and use it to backup the
    first one. That's the most reliable option.
     
    Lawrence D'Oliveiro, Jul 14, 2008
    #1
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  2. Lawrence D'Oliveiro

    Enkidu Guest

    Lawrence D'Oliveiro wrote:
    > In message <48785eae$>, thing wrote:
    >
    >> get 2 and raid1 it...and dont back up...

    >
    > Or get 2, put the second one in an older machine, and use it to backup the
    > first one. That's the most reliable option.
    >

    I like the idea of disk to disk backup in a second machine. But if you
    are talking TBytes that a considerable expense. Also you have to have a
    reliable method of keeping the two in sync. (I use rsync as I'm sure you
    remember). But disk to disk doesn't protect you against lost or damaged
    files, does it?

    Cheers,

    Cliff

    --

    "I LOVE IT!!" - someone on a newsgroup, somewhere.
     
    Enkidu, Jul 15, 2008
    #2
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  3. Lawrence D'Oliveiro

    JohnO Guest

    On Jul 15, 8:34 pm, Enkidu <> wrote:
    > Lawrence D'Oliveiro wrote:
    > > In message <>, thing wrote:

    >
    > >> get 2 and raid1 it...and dont back up...

    >
    > > Or get 2, put the second one in an older machine, and use it to backup the
    > > first one. That's the most reliable option.

    >
    > >

    > I like the idea of disk to disk backup in a second machine. But if you
    > are talking TBytes that a considerable expense. Also you have to have a
    > reliable method of keeping the two in sync. (I use rsync as I'm sure you
    > remember). But disk to disk doesn't protect you against lost or damaged
    > files, does it?
    >
    > Cheers,
    >
    > Cliff


    Disk to disk backups don't provide iterations of backups. What if a
    file got corrupted a week or month ago and you just realised it now?
    Too late if it's a disk backup runs daily.

    I'm speaking from a business perspective rather than a home computing
    one though. In my world, there is currently no feasible alternative to
    tapes. So what if your 1.5Tb database requires 4 LTO3 400Gb tapes in
    an automated library to back up? It's a small cost when weighed
    against the risk of going out of business due to a loss of enterprise
    critical data.
     
    JohnO, Jul 15, 2008
    #3
  4. Lawrence D'Oliveiro

    Enkidu Guest

    JohnO wrote:
    > On Jul 15, 8:34 pm, Enkidu <> wrote:
    >> Lawrence D'Oliveiro wrote:
    >>> In message <>, thing wrote:
    >>>> get 2 and raid1 it...and dont back up...
    >>> Or get 2, put the second one in an older machine, and use it to backup the
    >>> first one. That's the most reliable option.
    >> >

    >> I like the idea of disk to disk backup in a second machine. But if you
    >> are talking TBytes that a considerable expense. Also you have to have a
    >> reliable method of keeping the two in sync. (I use rsync as I'm sure you
    >> remember). But disk to disk doesn't protect you against lost or damaged
    >> files, does it?

    >
    > Disk to disk backups don't provide iterations of backups. What if a
    > file got corrupted a week or month ago and you just realised it now?
    > Too late if it's a disk backup runs daily.
    >

    Absolutely.
    >
    > I'm speaking from a business perspective rather than a home computing
    > one though. In my world, there is currently no feasible alternative to
    > tapes. So what if your 1.5Tb database requires 4 LTO3 400Gb tapes in
    > an automated library to back up? It's a small cost when weighed
    > against the risk of going out of business due to a loss of enterprise
    > critical data.
    >

    Well, actually a 1.5TB database would likely require 6 or more tapes,
    because the quoted 400GB is only a theoretical capacity, but it's the
    time that it takes which is the major problem.

    Cheers,

    Cliff

    --

    "I LOVE IT!!" - someone on a newsgroup, somewhere.
     
    Enkidu, Jul 15, 2008
    #4
  5. Lawrence D'Oliveiro

    EMB Guest

    Enkidu wrote:
    > Well, actually a 1.5TB database would likely require 6 or more tapes,
    > because the quoted 400GB is only a theoretical capacity, but it's the
    > time that it takes which is the major problem.



    I see a consistent 300GB/hr throughput on a single LTO4 drive on a
    mixture of shitty small files. With only larger files things should run
    a fair bit quicker. Even at 300GB/drive/hr a decent 3 drive tape robot
    would manage a 1.5TB backup in well under a couple of hours.

    That's pretty much as quickly as you could copy the data off to a SAN
    (which is what we do each night during the available backup window, then
    we backup the static copy on the SAN to tape via a single drive during
    the day when timeframes aren't an issue).
     
    EMB, Jul 15, 2008
    #5
  6. Lawrence D'Oliveiro

    JohnO Guest

    On Jul 15, 10:12 pm, Enkidu <> wrote:
    > JohnO wrote:
    > > On Jul 15, 8:34 pm, Enkidu <> wrote:
    > >> Lawrence D'Oliveiro wrote:
    > >>> In message <>, thing wrote:
    > >>>> get 2 and raid1 it...and dont back up...
    > >>> Or get 2, put the second one in an older machine, and use it to backup the
    > >>> first one. That's the most reliable option.

    >
    > >> I like the idea of disk to disk backup in a second machine. But if you
    > >> are talking TBytes that a considerable expense. Also you have to have a
    > >> reliable method of keeping the two in sync. (I use rsync as I'm sure you
    > >> remember). But disk to disk doesn't protect you against lost or damaged
    > >> files, does it?

    >
    > > Disk to disk backups don't provide iterations of backups. What if a
    > > file got corrupted a week or month ago and you just realised it now?
    > > Too late if it's a disk backup runs daily.

    >
    > Absolutely.
    > >> I'm speaking from a business perspective rather than a home computing

    > > one though. In my world, there is currently no feasible alternative to
    > > tapes. So what if your 1.5Tb database requires 4 LTO3 400Gb tapes in
    > > an automated library to back up? It's a small cost when weighed
    > > against the risk of going out of business due to a loss of enterprise
    > > critical data.

    >
    > >

    > Well, actually a 1.5TB database would likely require 6 or more tapes,
    > because the quoted 400GB is only a theoretical capacity, but it's the
    > time that it takes which is the major problem.
    >


    The time is only a problem if it interrupts production. All my clients
    run 24/7 with online backups null problemo.
     
    JohnO, Jul 15, 2008
    #6
  7. Lawrence D'Oliveiro

    Enkidu Guest

    EMB wrote:
    > Enkidu wrote:
    >> Well, actually a 1.5TB database would likely require 6 or more tapes,
    >> because the quoted 400GB is only a theoretical capacity, but it's the
    >> time that it takes which is the major problem.

    >
    > I see a consistent 300GB/hr throughput on a single LTO4 drive on a
    > mixture of shitty small files. With only larger files things should run
    > a fair bit quicker. Even at 300GB/drive/hr a decent 3 drive tape robot
    > would manage a 1.5TB backup in well under a couple of hours.
    >
    > That's pretty much as quickly as you could copy the data off to a SAN
    > (which is what we do each night during the available backup window, then
    > we backup the static copy on the SAN to tape via a single drive during
    > the day when timeframes aren't an issue).
    >

    What brand hardware? If you are willing to say? I'm looking at huge
    numbers of tiny files in a deep file system hierarchy. It takes 20 - 40
    minutes just to list the files in one of the systems, without actually
    reading them.

    Cheers,

    Cliff

    --

    "I LOVE IT!!" - someone on a newsgroup, somewhere.
     
    Enkidu, Jul 15, 2008
    #7
  8. In article <487c612c$>, Enkidu <> wrote:
    >Lawrence D'Oliveiro wrote:
    >> In message <48785eae$>, thing wrote:
    >>
    >>> get 2 and raid1 it...and dont back up...

    >>
    >> Or get 2, put the second one in an older machine, and use it to backup the
    >> first one. That's the most reliable option.
    > >

    >I like the idea of disk to disk backup in a second machine. But if you
    >are talking TBytes that a considerable expense. Also you have to have a
    >reliable method of keeping the two in sync. (I use rsync as I'm sure you
    >remember). But disk to disk doesn't protect you against lost or damaged
    >files, does it?


    A good point. First you need to decide what you are trying to protect
    against. Having multiple 'backups' will not save you if they are all in the
    same room and the building burns down ... for example. Similarly if the room
    is insecure, allowing someone to delete all files and backups. :)

    Different backup methods protect against different risks.
     
    Bruce Sinclair, Jul 16, 2008
    #8
  9. Lawrence D'Oliveiro

    Enkidu Guest

    JohnO wrote:
    > On Jul 15, 10:12 pm, Enkidu <> wrote:
    >> JohnO wrote:
    >>> On Jul 15, 8:34 pm, Enkidu <> wrote:
    >>>> Lawrence D'Oliveiro wrote:
    >>>>> In message <>, thing wrote:
    >>>>>> get 2 and raid1 it...and dont back up...
    >>>>> Or get 2, put the second one in an older machine, and use it to backup the
    >>>>> first one. That's the most reliable option.
    >>>> I like the idea of disk to disk backup in a second machine. But if you
    >>>> are talking TBytes that a considerable expense. Also you have to have a
    >>>> reliable method of keeping the two in sync. (I use rsync as I'm sure you
    >>>> remember). But disk to disk doesn't protect you against lost or damaged
    >>>> files, does it?
    >>> Disk to disk backups don't provide iterations of backups. What if a
    >>> file got corrupted a week or month ago and you just realised it now?
    >>> Too late if it's a disk backup runs daily.

    >> Absolutely.
    >> >> I'm speaking from a business perspective rather than a home computing
    >>> one though. In my world, there is currently no feasible alternative to
    >>> tapes. So what if your 1.5Tb database requires 4 LTO3 400Gb tapes in
    >>> an automated library to back up? It's a small cost when weighed
    >>> against the risk of going out of business due to a loss of enterprise
    >>> critical data.
    >> >

    >> Well, actually a 1.5TB database would likely require 6 or more tapes,
    >> because the quoted 400GB is only a theoretical capacity, but it's the
    >> time that it takes which is the major problem.
    >>

    >
    > The time is only a problem if it interrupts production. All my clients
    > run 24/7 with online backups null problemo.
    >

    How much data? How do you back up?

    Cheers,

    Cliff

    --

    "I LOVE IT!!" - someone on a newsgroup, somewhere.
     
    Enkidu, Jul 16, 2008
    #9
  10. Lawrence D'Oliveiro

    Enkidu Guest

    I LOVE IT! wrote:
    > Enkidu wrote:
    >> EMB wrote:
    >>> Enkidu wrote:
    >>>> Well, actually a 1.5TB database would likely require 6 or more
    >>>> tapes, because the quoted 400GB is only a theoretical capacity,
    >>>> but it's the time that it takes which is the major problem.
    >>> I see a consistent 300GB/hr throughput on a single LTO4 drive on
    >>> a mixture of shitty small files. With only larger files things
    >>> should run a fair bit quicker. Even at 300GB/drive/hr a decent 3
    >>> drive tape robot would manage a 1.5TB backup in well under a
    >>> couple of hours. That's pretty much as quickly as you could copy
    >>> the data off to a SAN (which is what we do each night during the
    >>> available backup window, then we backup the static copy on the
    >>> SAN to tape via a single drive during the day when timeframes
    >>> aren't an issue).
    >>>

    >> What brand hardware? If you are willing to say? I'm looking at huge
    >> numbers of tiny files in a deep file system hierarchy. It takes 20
    >> - 40 minutes just to list the files in one of the systems, without
    >> actually reading them.

    >
    > I use Acronis True Image to backup (incremental) my C: drive and data
    > drives to an external WD 500GB HD every night after I go to bed.
    > Works great. But I can see the day approaching where a bigger backup
    > HD will be needed.
    >
    > Perhaps one of these..
    >
    > http://www.pp.co.nz/products.php?pp_id=AA07436
    >
    > http://www.pp.co.nz/products.php?pp_id=AA06034 Raid
    >

    Thanks John, but I'm talking about much larger arrays spread over many
    machines.

    Does Acronis do a true backup or is it an image copy (plus
    incrementals)? If so, how many backup sets can you keep?

    Cheers,

    Cliff

    --

    "I LOVE IT!!" - someone on a newsgroup, somewhere.
     
    Enkidu, Jul 17, 2008
    #10
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