If you're going to implement a RAID solution, then you should look at RAID 10, but RAID is NOT a backup solution. To be safe, you should have remote offsite backups.
RAID configuration!
- Thread starter VerdinaNET
- Start date
It's worth saying: No matter who your provider is or what they promise - always make sure to have an off-site backup of your data unless you're willing to lose it.
And yes, RAID is not a backup. It also bears repeating
.vinahostsupport
New member
RAID 10 generally. RAID 6 is the other option. As it is a backup system the latency and throughput penalties of RAID 6 are not normally an issue and the risks, while much higher than RAID 10, aren't all that bad. I'm no fan of RAID 6 and likely would not do this myself, but it is not necessarily crazy either.
Be aware, though, that with RAID 6 you lose two disks to parity. With RAID 10 you lose three. So using RAID 6 you are, in a six drive array, very close to the penalties of RAID 10 and one could argue that you could just move to RAID 10 and have all of that safety.
Because this is a backup system and, in theory, losing it only means that you have to survive through a single additional round of backups before you are completely protected again, using something more risky like RAID 6 is not such a big deal.
Be aware, though, that with RAID 6 you lose two disks to parity. With RAID 10 you lose three. So using RAID 6 you are, in a six drive array, very close to the penalties of RAID 10 and one could argue that you could just move to RAID 10 and have all of that safety.
Because this is a backup system and, in theory, losing it only means that you have to survive through a single additional round of backups before you are completely protected again, using something more risky like RAID 6 is not such a big deal.
Raid 10 doesn't have 'parity' it has mirrors.
RAID 10 is short-hand for RAID 1+0.
You will have, at minimum, 2 RAID 1 mirrors (groups). In each group there are 2 disks and the contents of the two disks within one group is exactly the same.
Then you have a RAID 0 stripe across the two groups.
For more details -> http://www.thegeekstuff.com/2011/10/raid10-vs-raid01
You can lose one disk in both groups and survive but you cannot lose both disks in one of the groups. In short - it can give you *up to* 2 disks failure out of 4, but it can also die if you lose the wrong 2.
Raid 5 has enough parity data to cover the loss of a single disk and, while it has overhead, the parity calculations in Raid 5 are very fast/easy. When it comes to Raid 6 it's far more complicated with far more overhead using Galois Fields to compute parity but you can lose 2 disks no matter which two - but only 2.
RAID 6 is going to be more fault-tolerant than RAID 10 with a small number of disks because there are situations where losing 2 disks with RAID10 = data loss/array failure. There are no situations where losing 2 disks in RAID6 will destroy the array.
The issue with RAID 6 is that the larger the array gets - the more disks - the more likely you are to lose more than 2 disks. The parity data only protects you against 2 failures no matter how many disks you have. Your chance of disk failures goes up with more disks as well - the more you have, the more chances for failure.
It's a balancing act depending on what you need / want to do and how redundant you want it to be and how much capacity you can stand to lose in the process. RAID 6 is going to have a LOT more overhead so it will be slower to write than RAID10 but it should read pretty quick as parity isn't calculated on reads - just writes and rebuilds.
RAID 10 is short-hand for RAID 1+0.
You will have, at minimum, 2 RAID 1 mirrors (groups). In each group there are 2 disks and the contents of the two disks within one group is exactly the same.
Then you have a RAID 0 stripe across the two groups.
For more details -> http://www.thegeekstuff.com/2011/10/raid10-vs-raid01
You can lose one disk in both groups and survive but you cannot lose both disks in one of the groups. In short - it can give you *up to* 2 disks failure out of 4, but it can also die if you lose the wrong 2.
Raid 5 has enough parity data to cover the loss of a single disk and, while it has overhead, the parity calculations in Raid 5 are very fast/easy. When it comes to Raid 6 it's far more complicated with far more overhead using Galois Fields to compute parity but you can lose 2 disks no matter which two - but only 2.
RAID 6 is going to be more fault-tolerant than RAID 10 with a small number of disks because there are situations where losing 2 disks with RAID10 = data loss/array failure. There are no situations where losing 2 disks in RAID6 will destroy the array.
The issue with RAID 6 is that the larger the array gets - the more disks - the more likely you are to lose more than 2 disks. The parity data only protects you against 2 failures no matter how many disks you have. Your chance of disk failures goes up with more disks as well - the more you have, the more chances for failure.
It's a balancing act depending on what you need / want to do and how redundant you want it to be and how much capacity you can stand to lose in the process. RAID 6 is going to have a LOT more overhead so it will be slower to write than RAID10 but it should read pretty quick as parity isn't calculated on reads - just writes and rebuilds.
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serverbundle
New member
Raid 10 is the best. Very Stable and Reliable.
vinahostsupport
New member
Depends on what you are striving for:
Raw speed: RAID0
Mirroring: RAID1
Integrity + Speed: RAID5 (one disk parity)
Notes on each:
RAID0: If you lose one drive, you lose all data
RAID1: You have to cut your total drive size in half
RAID5: You lose one drive's worth of space, and need at least 3 drives. You will need to wait for the drive to rebuild if you replace a bad drive, and during a rebuild, if you lose a second drive, you will lose your data
You can also combine RAID configs to achieve different setups (RAID10, RAID50)
All being said, if you are looking for speed, but don't care about losing data, go RAID0, if you are looking to have a backup drive incase one goes down, go RAID1. RAID5 is good if you want some speed, and to have a backup incase on drive goes.
One thing to remember: RAID is never a backup solution
Raw speed: RAID0
Mirroring: RAID1
Integrity + Speed: RAID5 (one disk parity)
Notes on each:
RAID0: If you lose one drive, you lose all data
RAID1: You have to cut your total drive size in half
RAID5: You lose one drive's worth of space, and need at least 3 drives. You will need to wait for the drive to rebuild if you replace a bad drive, and during a rebuild, if you lose a second drive, you will lose your data
You can also combine RAID configs to achieve different setups (RAID10, RAID50)
All being said, if you are looking for speed, but don't care about losing data, go RAID0, if you are looking to have a backup drive incase one goes down, go RAID1. RAID5 is good if you want some speed, and to have a backup incase on drive goes.
One thing to remember: RAID is never a backup solution
VerdinaNET
New member
It's worth saying: No matter who your provider is or what they promise - always make sure to have an off-site backup of your data unless you're willing to lose it.
And yes, RAID is not a backup. It also bears repeating
I know it's not a backup
)PugetServers
New member
Raid 1- 2 Disks Same Size
Mirrors the files from one Disk to the Other.
E.G 2X 2TB Disk would give you Usable Space of 2TB and 2TB Reserved for backup.
Mirrors the files from one Disk to the Other.
E.G 2X 2TB Disk would give you Usable Space of 2TB and 2TB Reserved for backup.
Be carefull about employing the term Backup with raid. Some users might think that because they have Raid they don't need Backup.
Raid basicaly makes your disks more reliable but doesn't provide backup. You could have a currupt file that is synced to both of your raid drives resulting in a loss of data.
We have used both RAID 10 and RAID 50 setups, and when it comes to reliability, we wouldn't look back. There are additional things like having more frequently accessed data on Solid State drives (such as MySQL) and then RAIDing those too.
As others have a said, there are other ways of making backups, but the time it takes for a backup to restore can crush some businesses.
We currently work with a client that does between 3.5M and 4M per week - just 15 minutes of downtime can really hurt their business. But then, they're also running on a cloud system so they can enable and disable additional servers to handle the load as needed.
As others have a said, there are other ways of making backups, but the time it takes for a backup to restore can crush some businesses.
We currently work with a client that does between 3.5M and 4M per week - just 15 minutes of downtime can really hurt their business. But then, they're also running on a cloud system so they can enable and disable additional servers to handle the load as needed.
VerdinaNET
New member
Looks interesting and useful.
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