replace a raid 5 array

Is there a how to that explains how to replace a raid 5 arrya with a
completely new set of disks? I currently have a 3 disks in a RAID5,
each disk is 36GB, giving me 72GB of space. I want to replace all
three disks with 74GB disks, giving me a new capacity of 148GB; and of
course, migrate all the data over. Can anyone point me in the right
direction? Thanks.

Al

"Al" <bernala@gmail.com> wrote in message
news:1181741632.194564.223900@i38g2000prf.googlegr oups.com...
> Is there a how to that explains how to replace a raid 5 arrya with a
> completely new set of disks? I currently have a 3 disks in a RAID5,
> each disk is 36GB, giving me 72GB of space. I want to replace all
> three disks with 74GB disks, giving me a new capacity of 148GB; and of
> course, migrate all the data over. Can anyone point me in the right
> direction? Thanks.
>
> Al
>

If you system allows, just add the new disks, create a new Raid-5 set
side-by-side with the old set and copy/migrate all data from the old to the
new array. After that, remove the old disks, or leave them in if you need
the space.

Rob

At Wed, 13 Jun 2007 16:02:22 +0200 "Rob Turk" <wipe_this_r.turk@chello.nl> wrote:

>
> "Al" <bernala@gmail.com> wrote in message
> news:1181741632.194564.223900@i38g2000prf.googlegr oups.com...
> > Is there a how to that explains how to replace a raid 5 arrya with a
> > completely new set of disks? I currently have a 3 disks in a RAID5,
> > each disk is 36GB, giving me 72GB of space. I want to replace all
> > three disks with 74GB disks, giving me a new capacity of 148GB; and of
> > course, migrate all the data over. Can anyone point me in the right
> > direction? Thanks.
> >
> > Al
> >
>
> If you system allows, just add the new disks, create a new Raid-5 set
> side-by-side with the old set and copy/migrate all data from the old to the
> new array. After that, remove the old disks, or leave them in if you need
> the space.

Actually, all you need is one free 'slot'. Install one 74gig disk, copy
the existing RAID array over to this single disk, then pull all three of
the old disks, install three new 74 disks, create a new RAID-4 array,
copy from the single disk to the new RAID-5 array. Pull the extra disk
and have a static backup.

>
> Rob
>
>
>

--
Robert Heller -- 978-544-6933
Deepwoods Software -- Linux Installation and Administration
http://www.deepsoft.com/ -- Web Hosting, with CGI and Database
heller@deepsoft.com -- Contract Programming: C/C++, Tcl/Tk

"Robert Heller" <heller@deepsoft.com> wrote in message
news:57c42$46706c92$404a99a1$10992@news.news-service.com...
> At Wed, 13 Jun 2007 16:02:22 +0200 "Rob Turk" <wipe_this_r.turk@chello.nl>
> >> If you system allows, just add the new disks, create a new Raid-5 set
>> side-by-side with the old set and copy/migrate all data from the old to
>> the
>> new array. After that, remove the old disks, or leave them in if you need
>> the space.
>
> Actually, all you need is one free 'slot'. Install one 74gig disk, copy
> the existing RAID array over to this single disk, then pull all three of
> the old disks, install three new 74 disks, create a new RAID-4 array,
> copy from the single disk to the new RAID-5 array. Pull the extra disk
> and have a static backup.
>

Would you mind explaining how you do this with only 3 new disks available
(see OP), and how your RAID-4 suddenly turns into a RAID-5?

Rob

At Thu, 14 Jun 2007 07:27:17 +0200 "Rob Turk" <wipe_this_r.turk@chello.nl> wrote:

>
> "Robert Heller" <heller@deepsoft.com> wrote in message
> news:57c42$46706c92$404a99a1$10992@news.news-service.com...
> > At Wed, 13 Jun 2007 16:02:22 +0200 "Rob Turk" <wipe_this_r.turk@chello.nl>
> > >> If you system allows, just add the new disks, create a new Raid-5 set
> >> side-by-side with the old set and copy/migrate all data from the old to
> >> the
> >> new array. After that, remove the old disks, or leave them in if you need
> >> the space.
> >
> > Actually, all you need is one free 'slot'. Install one 74gig disk, copy
> > the existing RAID array over to this single disk, then pull all three of
> > the old disks, install three new 74 disks, create a new RAID-4 array,
> > copy from the single disk to the new RAID-5 array. Pull the extra disk
> > and have a static backup.
> >
>
> Would you mind explaining how you do this with only 3 new disks available

I am assuming the OP is getting some spares. If this is the same poster
who had a RAID system using 36gig Maxtor disks, that are no longer
available and was running out of spares and was looking for new spares.

> (see OP), and how your RAID-4 suddenly turns into a RAID-5?

The 'RAID-4' above was a typo. I meant RAID-5.

>
> Rob
>
>
>

--
Robert Heller -- 978-544-6933
Deepwoods Software -- Linux Installation and Administration
http://www.deepsoft.com/ -- Web Hosting, with CGI and Database
heller@deepsoft.com -- Contract Programming: C/C++, Tcl/Tk

Robert,

Yes, I was the guy posting about the Maxtor disks. I ordered some
74GB Cheetah drives from Seagate to have as spares (sitting on a
shelf, not installed). For now, the next time a Maxtor drive fails, it
will be replaced with a Seagate.

When one of the two remaining maxtors fail, it will also be
replaced with a Seagate drive. At which point, we'll do as you
suggested... copy data to new disk, remake raid 5 and copy data back.

Thanks everyone for your help.

"Al" <bernala@gmail.com> wrote in message
news:1181836711.132622.189370@a26g2000pre.googlegr oups.com...
> Robert,
>
> Yes, I was the guy posting about the Maxtor disks. I ordered some
> 74GB Cheetah drives from Seagate to have as spares (sitting on a
> shelf, not installed). For now, the next time a Maxtor drive fails, it
> will be replaced with a Seagate.
>
> When one of the two remaining maxtors fail, it will also be
> replaced with a Seagate drive. At which point, we'll do as you
> suggested... copy data to new disk, remake raid 5 and copy data back.
>
> Thanks everyone for your help.
>
If you have a suitable IDE drive, conect it and use GHOST to clone the
array onto the IDE. Change the RAID drives and create new array, then clone
IDE onto array, shutdown and remove IDE. Job done!

Mike.

Rob Turk wrote:
> "Robert Heller" <heller@deepsoft.com> wrote in message
> news:57c42$46706c92$404a99a1$10992@news.news-service.com...
>> At Wed, 13 Jun 2007 16:02:22 +0200 "Rob Turk" <wipe_this_r.turk@chello.nl>
>> >> If you system allows, just add the new disks, create a new Raid-5 set
>>> side-by-side with the old set and copy/migrate all data from the old to
>>> the
>>> new array. After that, remove the old disks, or leave them in if you need
>>> the space.
>> Actually, all you need is one free 'slot'. Install one 74gig disk, copy
>> the existing RAID array over to this single disk, then pull all three of
>> the old disks, install three new 74 disks, create a new RAID-4 array,
>> copy from the single disk to the new RAID-5 array. Pull the extra disk
>> and have a static backup.
>>
>
> Would you mind explaining how you do this with only 3 new disks available
> (see OP), and how your RAID-4 suddenly turns into a RAID-5?
>
> Rob
>
>
Isn't there a way to create a RAID-5 with a "failed disk" with mdadm?

I know this could be done with raidtools...

Then you can create a RAID-5 w/ 2 74 GB drives and no spares, but with
one "failed" drive. Then copy your data from the third 74 GB drive (the
"failed" one), verify, bring the "failed" drive on line, and you're done....

--Yan