redl1ne
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3 of 4 hard drives for RAID 5?
I know the minimum required is 3, but I remember hearing somewhere you should always go with at least 4 to make up for space taken up by parity.
Are there any other advantages to having 4 instead of 3? Thanks..
Are there any other advantages to having 4 instead of 3? Thanks..
What kind of RAID ??? /0,1,3,5,10 :-)))/Every type uses it's own set of HDD. RAID 1 /disk mirroring/ uses 2,4 i.e HDD's, RAID 3,5 uses at least 3 or more HDD, RAID 10 uses min 4 disks.
ASKER
RAID 5 dude (it's in the topic! :P)
I just want to know if hard drive space is not an issue, if 4 gives you any more of an advantage than 3.
I just want to know if hard drive space is not an issue, if 4 gives you any more of an advantage than 3.
Not really other than a little extra speed and one more drive that can fail without a total collapse.
ASKER
RAID 5 dude (it's in the topic! :P)
I just want to know if hard drive space is not an issue, if 4 gives you any more of an advantage than 3.
I just want to know if hard drive space is not an issue, if 4 gives you any more of an advantage than 3.
ASKER
Weed, are you saying that if I have 4 drives and 2 fail, my data is ok?
From my understanding, you can have as many drives as you want, but if more than 1 drive dies, you're screwed?
From my understanding, you can have as many drives as you want, but if more than 1 drive dies, you're screwed?
Redl1ne you are correct unless you go with a hot spare. Where I work we would always go with 4 or more drives. With 4 drives you do 3 drivs raid 5 with a hot spare. This way you can lose one drive and still have your raid so that you still have the fault tolerance. In other words you can loose 2 drives. Remember that this is only if you use a hot spare.
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The advantages of a RAID-5 with 4 disks inatead of 3 disks are:
- increased read & write speed
- increased storage capacity
- increased cache memory capacity
- 50% capacity increase vs 25% cost increase - as magarity eplained
That's all I can think of right now.
- increased read & write speed
- increased storage capacity
- increased cache memory capacity
- 50% capacity increase vs 25% cost increase - as magarity eplained
That's all I can think of right now.
Member '1175089' say type of RAID.
You know RAID at least 3 HDD. This is RAID 5.
And then 4,5,6......20 run at RAID 5.But, this is at SCSI performanes, not IDE.
Now IDE RAID only support RAID 0,1,0+1.
Adaptec IDE RAID card, still support RAID 5.But the card at manket so little.
You know RAID at least 3 HDD. This is RAID 5.
And then 4,5,6......20 run at RAID 5.But, this is at SCSI performanes, not IDE.
Now IDE RAID only support RAID 0,1,0+1.
Adaptec IDE RAID card, still support RAID 5.But the card at manket so little.
colinccm. Then what has Promise been making the last few years? (http://www.promise.com/)
Several manufacturers make IDE RAID cards; the biggest I've seen takes up to 12 drives. The real mystery is colinccm's last sentence... I wonder from what country is he/she.
BTW, I've used a 512 byte sector size in my example, but good controllers let you select your own. Most have a recommended size for their respective processors. So use whatever that is for your calculations.
redl1ne, do you have any followup questions?
BTW, I've used a 512 byte sector size in my example, but good controllers let you select your own. Most have a recommended size for their respective processors. So use whatever that is for your calculations.
redl1ne, do you have any followup questions?
ASKER
Very informative post. Thanks to all!