Re: Disk partitioning question
- From: "SuperGumby [SBS MVP]" <not@xxxxxxxxxxx>
- Date: Fri, 8 Jul 2005 01:58:21 +1000
I gotta point out though:
depending on the controller John's RAID5 may or not yet be a drive available
to the OS.
A hardware RAID Volume may exist without any RAID Drives on it. (again, I
stress, this depends on the controller) Adding spindles may increase the
defined size of the RAID Volume but the increase in space is not yet
apparent to the OS, either the existing RAID Drives must be adjusted or
additional RAID Drives created, at which time the change becomes visible to
the OS.
Some controllers (a Compaq comes to mind) allow you to connect 3*36GB
spindles and define a 500GB RAID5 Volume. Of course, only 72GB is available
to be assigned as RAID Drives. If you add spindles to the set the usable
space for RAID Drives increases and you may even adjust the size of the
available RAID Drives, or create additional ones. It is at this point that
we start talking about what 'drives' appear as available to the OS and how
they may be created as Windows partitions and/or volumes.
"John Vollman" <nospam@xxxxxxxxxxx> wrote in message
news:upZhRdwgFHA.3656@xxxxxxxxxxxxxxxxxxxxxxx
> To continue with SuperGumby's brain dump:
>
> Creating a single hardware based RAID 5 using all disks is not the highest
> performing configuration for the OS, Exchange or SQL but is generally the
> best tradeoff between performance, reliability and ease of management.
> This single array will show up as Disk 0 in Windows Disk Manager.
> Creating a C: drive partition of 20GB for the OS and apps and a data
> partion with the rest of the drive will allow you to reformat and
> reinstall the OS and apps if the @#$! hits the fan without messing with
> your data. All of the SBS applications allow you to move their respective
> data stores to another location. So you can install Exchange and SQL on
> the C drive but then move the stores, logs and mail pickup directories to
> the data drive. This does take a lot of time/effort so you could just
> install Exchange and SQL onto the data drive. You want to be carefull
> with leaving Exchange, ISA and SQL data on the C drive as their log files
> will fill up your C drive if you don't keep an eye on them.
>
> The nice thing about doing it this way is if you ever get tight on space
> you can add drives to the RAID array to use for data. When you add a new
> drive to the RAID, you do this throught the array management utility
> during POST or a software interface, the drive will show up in Disk
> Manager as unpartitioned space. You can extend the last partion on Disk
> 0, your data partition, onto this new space. This is really easy if you
> convert your Disk 0 to a dynamic volume.
>
> This by no means is an ideal configuration if you have a busy system. And
> in fact is contrary to everything you will read from Microsoft regarding
> the deployment of Exchange and SQL. But for the average SBS it will do
> quite nicely.
>
> And since simplicity is a halmark of the SBS product you should KISS.
>
>
> John Vollman
>
>
>
>
>
>
> "SuperGumby [SBS MVP]" <not@xxxxxxxxxxx> wrote in message
> news:%23QruKWvgFHA.3540@xxxxxxxxxxxxxxxxxxxxxxx
>> terminology is a kicker on this one, let me see if I can explain why.
>> and keep in mind that it depends on the RAID controller.
>>
>> Take a number of drives and connect them to a RAID controller, let's be
>> ridiculous and use 10 HDD's (herewith called 'spindles').
>>
>> One choice you could make would be to implement a single RAID Volume, all
>> 10 spindles RAID5, let's say. At this point you do not have any Windows
>> drives, partitions or volumes.
>> The RAID Volume can then be divided into RAID Drives. These will appear
>> as blank disks to windows.
>> On some controllers a RAID Volume and RAID Drive are the same thing.
>> (Particularly on cheap nasty IDE/SATA RAID, which should not be used on
>> primary servers).
>> Lets take our single RAID Volume and divide it into 6 RAID Drives, just
>> for fun. :-)
>>
>> We can now use Windows to do stuff to the blank drives.
>> On the first RAID Drive we're going to install the OS, then software
>> mirror it to the 2nd RAID Drive. SO, we use Windows, after install, to
>> make them 'dynamic' and create a single Windows software RAID 1 volume
>> betwixt the two.
>> We're also severely paranoid about our DATA so we're going to take the
>> other four RAID Drives and create a Windows software RAID 5 set (volume)
>> out of them.
>> We don't actually need to use all the space on each RAID Drive for our
>> windows volumes, so let's get even more tricky, let's throw some more
>> numbers into the mix.
>>
>> Our 10 spindles are 36GB SCSI drives, so our hardware RAID5 Volume is
>> 324GB, equally divided into 6 hardware RAID Drives, so each appears to
>> the OS as a 54GB drive. We want no more than 20GB for our OS so
>> Windows/drive0 is divided into 20GB OS and rest, and is software mirrored
>> to Windows/drive1. The DATA partition takes the remaining space from both
>> these and available space on the other four Windows drives for a 6*34
>> RAID5 set (usable 170GB) and we're left with 4*20GB for a Windows
>> software RAID0 volume for our swap file and temp stuff (usable 80GB).
>>
>> Is this setup silly? In relation to SBS it's probably about as silly as
>> you can get, but HECK, there's a lot of SBS installers out there doing
>> stuff just as STUPID and charging people for it. (yes, /cynic_mode_on
>> today). In an enterprise environment this could actually make sense, but
>> would probably involve multiple hardware RAID Volumes.
>>
>> TIME PASSES, and, as expected, we run out of room. WELL, there's room on
>> that SCSI bus for a couple more spindles, let's add four 36's.
>>
>> At first, nothing happens. The spindles appear as additional items to the
>> RAID controller and that's IT. Windows is not aware of them.
>> (depending on the controller) we could:
>> a) create another hardware RAID Volume
>> b) incorporate the spindles into the existing hardware RAID Volume
>> let's incorporate!!!!
>>
>> SO, we do our tricky thing which takes anything from a few minutes to
>> many days and suddenly our hardware RAID Volume is 468GB.
>> More trickiness and we create additional hardware RAID Drives, suffering
>> from a severe attack of sensibility we create two additional hardware
>> RAID Drives of the same size as our existing set, 54GB. Does Windows have
>> any more space??? NO, it has another couple of blank drives to play with.
>> We then need to use some form of DOS/Windows drive manipluation
>> (Partition/Server Magic comes to mind) to adjust our Windows
>> partitions/volumes to use the additional space.
>>
>> Project your 3-5yr data growth as best you can.
>> Implement a single hardware RAID5 volume of sufficient size to hold your
>> 20GB OS + projected DATA.
>> Add a hotspare spindle.
>>
>>
>> "Nikki" <Nikki@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in message
>> news:8E5BF8A2-FFF4-40BB-B3D4-2A747C2FB661@xxxxxxxxxxxxxxxx
>>> Hi !
>>> I am installing a new SBS 03 server which will come with hardware RAID5
>>> disk
>>> space. Shall I create partitions or volumes ? I was planning to create 3
>>> areas - one for system, one for exchange, one for users data. Also, I
>>> planned
>>> not to use the whole space but to leave free space to extend
>>> partitions/volumes - can I do that on the fly?- when I need to. Is
>>> that a
>>> good idea?
>>> Thanks!!
>>>
>>> --
>>> Nikki It Admin
>>
>>
>
>
.
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