[nflug] RAID
Eric #4011
eric at bootz.us
Mon Feb 11 12:09:42 EST 2008
Ok, decided
/boot RAID1 3 active and 1 spare -1GB
/SWAP RAID1 3 active and 1 spare -2GB
/ RAID5 3 active and 1 spare -MAX
then made / RAID 5 and LVM volume group
Eric #4011 wrote:
> I really like the RAID 0+1 idea but I'm not sure how to do it with
> Linux software RAID, do I need to create two RAID 0's and then combine
> them with a nested RAID 1 to achieve RAID 0+1. I will consider RAID 5
> as suggested.
>
>
> Corey Reichle wrote:
>> You need to consider this: RAID0 is the best performance wise, but
>> at the risk of a single drive going will bring down the array.
>>
>> RAID1 will get you some fault tolerance, but it takes a hit since two
>> physical writes for every logical write. The only way to circumvent
>> much of the performance loss is separate controllers.
>>
>> I would suggest RAID5. Best performance gain for fault tolerance, as
>> well as increased performance over a RAID0 with the right controllers.
>>
>> ====================
>> From: Eric #4011 <eric at bootz.us>
>> Date: 2008/02/11 Mon AM 07:01:46 CST
>> To: nflug at nflug.org
>> Subject: Re: [nflug] RAID
>>
>> Great, I'll use Raid Software then.
>>
>> Space isn't a problem each drive is 160GB and it's just a small email
>> server of about 100 people, so raid 0 or 1 would be best for
>> performance?
>> these are also hot swap drives does a certain raid matter in this
>> instance?
>>
>> Thank you,
>> Eric
>>
>> Mark Musone wrote:
>>
>>> I'd probably use software raid over most onboard SATA raid
>>> controllers..
>>>
>>> You may also want to consider raid-5, since you'll get more usable
>>> storage
>>> space than raid0-1
>>>
>>> Mark
>>>
>>>
>>> -----Original Message-----
>>> From: nflug-bounces at nflug.org [mailto:nflug-bounces at nflug.org] On
>>> Behalf Of
>>> Eric #4011
>>> Sent: Friday, February 08, 2008 3:36 PM
>>> To: nflug at nflug.org
>>> Subject: Re: [nflug] RAID
>>>
>>> Yes it does help, and I want to be sure I do this the right way.
>>> The board is a TYAN Tomcat K8E using a Nvidia RAID controller for
>>> SATA drives... I have heard that the onboard RAID controllers are
>>> not that great, however which is better poison the Linux RAID
>>> software or the onboard RAID controller?
>>>
>>> Rob Dege wrote:
>>>
>>>> It's been a while since I've spoken in RAID, but I think your
>>>> terminology is off. RAID-0 by default requires at least two hard
>>>> drives in order to configure. The same goes for RAID 1.
>>>>
>>>> So, in this instance, you will use two drives to create a RAID-0
>>>> array. This array now appears as a single drive. You then create
>>>> another RAID-0 array using the other two disks. This array now
>>>> appears as a single drive. So now, you have two RAID0 arrays
>>>> independent of each other. Finally, you create a RAID-1 mirroring
>>>> array, using the two RAID-0 disks that you just created.
>>>>
>>>> Thus, you now have a single drive, with the capacity of two
>>>> drives. If this is all handled within the RAID controller, linux
>>>> will only acknowledge the existence of this RAID-0+1 drive as a
>>>> single disk. So you won't be able to use the linux software RAID
>>>> to create another layer of mirroring.
>>>>
>>>> Of course, this is assuming that your RAID controller is doing all
>>>> of the array structure and work. Most of the onboard RAID
>>>> controllers in today's motherboards, and built shoddy. Their
>>>> contain the cheap hardware, but you need to install software to
>>>> configure/access the onboard controller.
>>>>
>>>> Plus, it's been a while, but I do recall some warning about not
>>>> putting either the root directory or the /boot directory on a
>>>> raid. It has something to do about the module needed by the kernel
>>>> to identify the raid drive being stored on the raid drive or
>>>> something like that.
>>>>
>>>> oh well, hope this helps somewhat.
>>>>
>>>> -Rob
>>>>
>>>>
>>>> On Feb 8, 2008 12:49 PM, Eric #4011 <eric at bootz.us
>>>> <mailto:eric at bootz.us>> wrote:
>>>>
>>>> Hi, I was wondering if the following RAID configuration is
>>>> possible?
>>>>
>>>>
>>>> I have 4 SATA drives for RAID and am using MediaShield utility to
>>>> configure a RAID 0+1
>>>>
>>>>
>>> ****************************************************************************
>>>
>>> *******************
>>>
>>>> MediaShield States RAID 0+1 is:
>>>> RAID 0 drives can be mirrored using RAID 1 techniques,
>>>> resulting in a RAID 0+1 solution
>>>> for improved performance plus resiliency
>>>> The controller combines the performance of data
>>>> striping (RAID
>>>> 0) and the fault tolerance
>>>> of disk mirroring (RAID 1). Data is striped across
>>>> multiple
>>>> drives and duplicated on
>>>> another set of drives.
>>>>
>>>>
>>> ****************************************************************************
>>>
>>> *******************
>>>
>>>> After this I have two drives and I am ready to install
>>>> linux(debian etch)
>>>>
>>>> My thoughts are if I also use RAID 1 software(linux) with the
>>>> existing
>>>> two drives I will have one hard drive writing to three hard
>>>> drives?
>>>>
>>>> I'm wondering if this is possible?
>>>>
>>>> Thank you in advance for your explanations
>>>>
>>>> Thank you,
>>>> Eric
>>>> _______________________________________________
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>>>>
>>>>
>>>>
>>>> --
>>>> -Rob
>>>>
>>>> Ben Franklin Quote: "They that can give up essential liberty to
>>>> obtain a little temporary safety deserve neither liberty nor safety."
>>>> ------------------------------------------------------------------------
>>>>
>>>>
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