do you have a spare for your RAID array?

[Fullmetal Chocobo]

Just wondering. I'm thinking about putting in 250gb & 160gb spares in my arrays, and I wanted to see what everyone else has.

If you post, please mention what RAID type you are using, and what type of spare you have (if you have one).

 

[LxMxFxD3]

I run a 3 disk raid 5 setup. No spare required. If one fails I'll just take a slight performance hit till the replacement arrives...

 

[Some1ne]

RAID-0 with 2 raptors, no backup, no spare, no worries.

 

[SnoMunke]

Originally posted by: LxMxFxD3
I run a 3 disk raid 5 setup. No spare required. If one fails I'll just take a slight performance hit till the replacement arrives...

Slight performance hit????? :shocked: Yeah I say so since you won't be able to access ANY of your data until you install the new drive and rebuild the RAID array...

Might want to read up on RAID 5 a bit...AND you might want to get a spare...

Only RAID array that still allows full access to data if one (or two drives) fail is RAID 1, 01, 10, and 6.

 

[Fullmetal Chocobo]

Originally posted by: SnoMunke

Originally posted by: LxMxFxD3
I run a 3 disk raid 5 setup. No spare required. If one fails I'll just take a slight performance hit till the replacement arrives...

Slight performance hit????? :shocked: Yeah I say so since you won't be able to access ANY of your data until you install the new drive and rebuild the RAID array...

Might want to read up on RAID 5 a bit...AND you might want to get a spare...

Only RAID array that still allows full access to data if one (or two drives) fail is RAID 1, 01, 10, and 6.

Huh? Um, you might want to check where you are getting your info. Sorry, but RAID 5 allows data access with a drive down. I know this from experience. It does for the array to go critical, but you can still use the array.

 

[Some1ne]

Yes, a RAID-5 can still function if a single drive fails. It slows down substantially, because the missing data has to be reconstructed on the fly from what's still there, but it keeps working nonetheless.

 

[LxMxFxD3]

Originally posted by: SnoMunke

Originally posted by: LxMxFxD3
I run a 3 disk raid 5 setup. No spare required. If one fails I'll just take a slight performance hit till the replacement arrives...

Slight performance hit????? :shocked: Yeah I say so since you won't be able to access ANY of your data until you install the new drive and rebuild the RAID array...

Might want to read up on RAID 5 a bit...AND you might want to get a spare...

Only RAID array that still allows full access to data if one (or two drives) fail is RAID 1, 01, 10, and 6.

Might want to stop hitting the crack pipe kid.

Yes if I lose a drive I'd lose performance - well worth a performance hit to keep my crucial data safe - but no I wouldn' tlose performance. Besides, I'd prolly have to wait a max of 3 days (MAX) for a new drive to arrive.

 

[SnoMunke]

Originally posted by: LxMxFxD3

Originally posted by: SnoMunke

Originally posted by: LxMxFxD3
I run a 3 disk raid 5 setup. No spare required. If one fails I'll just take a slight performance hit till the replacement arrives...

Slight performance hit????? :shocked: Yeah I say so since you won't be able to access ANY of your data until you install the new drive and rebuild the RAID array...

Might want to read up on RAID 5 a bit...AND you might want to get a spare...

Only RAID array that still allows full access to data if one (or two drives) fail is RAID 1, 01, 10, and 6.

Might want to stop hitting the crack pipe kid.

Yes if I lose a drive I'd lose performance - well worth a performance hit to keep my crucial data safe - but no I wouldn' tlose performance. Besides, I'd prolly have to wait a max of 3 days (MAX) for a new drive to arrive.

Don't EVER disrespect my crack pipe!

I don't think you are understanding what I am schooling you on...in a RAID 5 array the data and parity are striped across all drives. When one drive fails, the parity from the other drives will allow the data to be recovered (array rebuilt) once a new drive is installed. Until that drive is replaced, your RAID array is unreadable and you have NO access to your data.

If you have a hot spare, the array can be rebuilt automatically by the system; however, you will still have downtime (no access) to your data until the array rebuilding is complete. This is not a performance hit dude...this a complete failure of access.

Are you following me now?

If you want a performance hit and NO downtime, you need to run RAID 1, 01, 10, or 6.

As I said before, you should be running a hot-spare when using RAID 5.

 

[Fullmetal Chocobo]

Originally posted by: SnoMunke

Originally posted by: LxMxFxD3

Originally posted by: SnoMunke

Originally posted by: LxMxFxD3
I run a 3 disk raid 5 setup. No spare required. If one fails I'll just take a slight performance hit till the replacement arrives...

Slight performance hit????? :shocked: Yeah I say so since you won't be able to access ANY of your data until you install the new drive and rebuild the RAID array...

Might want to read up on RAID 5 a bit...AND you might want to get a spare...

Only RAID array that still allows full access to data if one (or two drives) fail is RAID 1, 01, 10, and 6.

Might want to stop hitting the crack pipe kid.

Yes if I lose a drive I'd lose performance - well worth a performance hit to keep my crucial data safe - but no I wouldn' tlose performance. Besides, I'd prolly have to wait a max of 3 days (MAX) for a new drive to arrive.

Don't EVER disrespect my crack pipe!

I don't think you are understanding what I am schooling you on...in a RAID 5 array the data and parity are striped across all drives. When one drive fails, the parity from the other drives will allow the data to be recovered (array rebuilt) once a new drive is installed. Until that drive is replaced, your RAID array is unreadable and you have NO access to your data.

If you have a hot spare, the array can be rebuilt automatically by the system; however, you will still have downtime (no access) to your data until the array rebuilding is complete. This is not a performance hit dude...this a complete failure of access.

Are you following me now?

If you want a performance hit and NO downtime, you need to run RAID 1, 01, 10, or 6.

No. That is simply not right. When you lose a drive with RAID 5, the array goes critical, which means that is no longer fault tolerant. So you can lose 1 drive, but not 2. However, the information is still available, and you can use the array just fine, albeit with a performance hit.

 

[SnoMunke]

tasburrfoot78362,

What kind of RAID arrays are you running now? Are you using nested arrays?

 

[Fullmetal Chocobo]

5 disk RAID 5 array. I had a drive go down recently, and had to return the drive and all that, but I stayed operational. I'm going to be migrating the array to a 6 disk RAID 5 array soon though.

EDIT: Oh, and this is on a Broadcom BC4852 PCI-X RAID controller (64-bit @ 133MHz bus)

 

[LxMxFxD3]

Originally posted by: SnoMunke

Originally posted by: LxMxFxD3

Originally posted by: SnoMunke

Originally posted by: LxMxFxD3
I run a 3 disk raid 5 setup. No spare required. If one fails I'll just take a slight performance hit till the replacement arrives...

Slight performance hit????? :shocked: Yeah I say so since you won't be able to access ANY of your data until you install the new drive and rebuild the RAID array...

Might want to read up on RAID 5 a bit...AND you might want to get a spare...

Only RAID array that still allows full access to data if one (or two drives) fail is RAID 1, 01, 10, and 6.

Might want to stop hitting the crack pipe kid.

Yes if I lose a drive I'd lose performance - well worth a performance hit to keep my crucial data safe - but no I wouldn' tlose performance. Besides, I'd prolly have to wait a max of 3 days (MAX) for a new drive to arrive.

Don't EVER disrespect my crack pipe!

I don't think you are understanding what I am schooling you on...in a RAID 5 array the data and parity are striped across all drives. When one drive fails, the parity from the other drives will allow the data to be recovered (array rebuilt) once a new drive is installed. Until that drive is replaced, your RAID array is unreadable and you have NO access to your data.

If you have a hot spare, the array can be rebuilt automatically by the system; however, you will still have downtime (no access) to your data until the array rebuilding is complete. This is not a performance hit dude...this a complete failure of access.

Are you following me now?

If you want a performance hit and NO downtime, you need to run RAID 1, 01, 10, or 6.

As I said before, you should be running a hot-spare when using RAID 5.

I TOLD YOU ONCE AND I'LL TELL YOU AGAIN:

STOP HITTING THE CRACK PIPE!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Just to prove you wrong I just unpluged disk 2 of my 3 disk array.

STILL WORKS!!!!!!!! MUHAHAHAHAHA.

 

[svi]

tasburrfoot is correct, IIRC.

To elaborate: recall that if one disk goes down in a three-disk RAID 5 array, there is no actual loss of data. As a result, it is quite possible to read all data from the remaining two drives-- it is all there, and the system is already well-equipped to read the data in the form it's in (what do you think the controller DOES?). It is also possible to continue writing data as normal to the two remaining drives and discarding relevant redundant data and parity information that would normally go to the third drive. Since all of this information is redundant and thus can be (obviously IS) reconstructed when a new third is placed in the system, it's a simple matter to read data from or add more data to the remnants of the array in the meantime.

Of course, utilizing an array that has gone critical is a bad idea, and your RAID controller will be sure to let you know this. It's possible, though, and it's better than the alternative in many cases.

It is entirely possible that there are controllers out there that do not let critical RAID 5 arrays run normally. I've not encountered them, though.

 

[Some1ne]

When one drive fails, the parity from the other drives will allow the data to be recovered (array rebuilt) once a new drive is installed. Until that drive is replaced, your RAID array is unreadable and you have NO access to your data.

False. To reiterate what everyone else has probably already been saying, consider that in order to rebuild the array after swapping in a new disk, the system needs to possess some way of reconstructing the data that was lost (which it does, in the form of the striped parity data). If you can reconstruct the data, it logically follows that you can continue to service requests for the data, all you have to do is reconstruct the parts of it that are missing (on the fly), and you can service the request. Obviously reconstructing missing data is a compute intensive operation, so there is a performance hit, but the failure of one drive in a RAID-5 array does not disable the array.

 

[Fullmetal Chocobo]

Maybe this will help some. Fault tolerancy is when a drive can go down, and still operational. This is the definition of a RAID array (hence, redundant). And the only RAID array not capable of this is RAID 0.

 

[SnoMunke]

I wonder how long Anandtech.com keeps record of my very apparent n00bness, stupidity, etc. etc.?

Will my great-grandchildren get to see my posts in the future and say "And there is the writings of our great-grandfather that was disowned by the family and whose name we are never to speak of"?

I will swallow my pride...admit I was/am wrong...although the crack pipe had NOTHING to do with it.

As I was getting caught up with the concern of repairing the array, I did forget the RAID controller will still be able to calculate parity from the other drives to re-create the data on the fly (which would be stored in RAM).

Since my pride is sorely injured and I tend to lash out at all those around me....hehe...I will say this:

LxMxFxD3, you are a dumbAHHHSSSS if you spend all the money on a RAID 5 systems and are too cheap to buy a hot-spare. (But, then again, you are probably using a onboard RAID 5 option which I don't think gives you the option to have a hot-spare standing by...so HENCE I cannot fault you and deem you to be a dumbAHHHSSSS...)

Damn, it there any way out of this complete and total embarrassment and humilation?

The 800lb. gorilla has been SCHOOLED!!!!

 

[SnoMunke]

By the way, I am thinking about setting up a nested RAID array using 2 different controllers... tasburrfoot78362, I let you know the performance of the array if I do it....

 

[Fullmetal Chocobo]

Originally posted by: SnoMunke
By the way, I am thinking about setting up a nested RAID array using 2 different controllers... tasburrfoot78362, I let you know the performance of the array if I do it....

What bus are you going to be doing this on, and what controllers are you going to be using, if you don't mind me asking?

Originally posted by: SnoMunke
LxMxFxD3, you are a dumbAHHHSSSS if you spend all the money on a RAID 5 systems and are too cheap to buy a hot-spare. (But, then again, you are probably using a onboard RAID 5 option which I don't think gives you the option to have a hot-spare standing by...so HENCE I cannot fault you and deem you to be a dumbAHHHSSSS...)

Damn, it there any way out of this complete and total embarrassment and humilation?

The 800lb. gorilla has been SCHOOLED!!!!

And you were alright until you started picking on someone. There is no need to have a hot-spare, so long as you are willing to accept the risks of running a critical array (or able to leave the machine off until you replace it). No need to call someone a dumbass because they choose to do so.

 

[SnoMunke]

Originally posted by: tasburrfoot78362

What bus are you going to be doing this on, and what controllers are you going to be using, if you don't mind me asking?

And you were alright until you started picking on someone. There is no need to have a hot-spare, so long as you are willing to accept the risks of running a critical array (or able to leave the machine off until you replace it). No need to call someone a dumbass because they choose to do so.

First, I wasn't picking on him. I was just pointing out (light-heartedly I might add) that if he were spending money to create a RAID array, he should finish the job and have a hot-spare standing by. Just punking him out...no harm intended.


Second,

Bus? Well, the yellow one...just kidding. Two Areca ARC-1210 cards would be cool, but...are there any boards out there with 2 x8 PCI-E ports? Yes, I know this is what SLI is, but what do I use for video? PCI? YUCK!

So, since I live here in Japan, and they have this awesome company called Kuro Box that makes PC parts CHEAP, I currently have a $50 2-port SATA II PCI-E x1 card. I am looking to see if they make a 4-port version. Many motherboards have a x4 and x1 PCI-E port so I can take 2 PCI-E x1 cards and use them in the nested array.

Sound cool?