A raidy question.... What would you use??

[phill]

I'm planning on changing around my raid 1 on my Synology system as I'm running low on space and I'm looking to buy bigger drives.

Currently I have 6 4Tb drives, they are setup in pairs for a raid 1 giving me 12Tb of usable space (ish).

I'm looking to buy 12Tb drives for extra storage but I was wondering how anyone might suggest to set them up... Raid 1 I think I'm loosing a bit of storage for how I've set up the volumes (3 separate ones not just 1 big volume) so I was wondering if a Raid 5 or even 6 might have been a better option?

I just thought I'd ask people here and see what their preference might be? I've done a little pole as well just for info really, so thanks in advance if you vote

 

[qubit]

You always lose half your storage when you're configuring for data redundancy and can't be helped. Just raid 1 the 12TB drives and you'll be good to go.

EDIT: there seems to be some misunderstanding on what I explained above. What I'm saying is that even though there's 24TB of storage between the two drives, you'll only be able to see 12TB since the drives mirror each other for data redundancy. That's what I mean by "losing storage space" and I would have thought you guys would have got that.

 

[FordGT90Concept]

How many 12 TB drives are you thinking about buying?

RAID1 is ideal with two drives.
RAID5 is ideal with three-four drives.
RAID6 is ideal with more than four drives. Beware that RAID6 controller cards aren't cheap.

 

[Vayra86]

I stopped raiding, only playing solo now

Wait...

 

[phill]

You always lose half your storage when you're configuring for data redundancy and can't be helped. Just raid 1 the 12TB drives and you'll be good to go.

How many 12 TB drives are you thinking about buying?

RAID1 is ideal with two drives.
RAID5 is ideal with three-four drives.
RAID6 is ideal with more than four drives. Beware that RAID6 controller cards aren't cheap.

Thanks for the replies guys, appreciated

I was currently thinking about doing another Raid 1 volume (so would be a total of 4 volumes and 8 drives) but I wondered if I could get say 4 drives, Raid 5 them, have about 36Tb space ish then and use the 4Tb drives as backups for the Raid 5 array?
I think the single extra Raid 1 volume would be the easiest but I'd still end up needing 3 drives - 2 for the Raid 1 and then another for a backup drive that would sit outside the NAS.

As for how many I'd be buying, I'd say @FordGT90Concept , a minimum of at least 3 and then depending on if I'd like an extra or two for being able to backup the data else where. Raid only good for so much, so I have to make sure I had another copy of it else where I'm a little OCD to be honest at that point

As for the Raid 6, I believe I could use one of the server cards I have currently downstairs in the rack of servers I've had from work. I'm unsure though if the Synology system I use would be able to handle that level of raid? Currently I just use the software model from Synology under Raid 1. I'll see if I can add in another drive and just see what levels of Raid it will work with

I stopped raiding, only playing solo now

Wait...

I laughed, I liked

 

[Athlonite]

Why not RAID0+1 speed and redundancy

 

[Aquinus]

You always lose half your storage when you're configuring for data redundancy and can't be helped. Just raid 1 the 12TB drives and you'll be good to go.

Wrong. You always lose as least half of your storage when you use RAID-1 which literally makes it the least effective option and that's assuming you only have one copy of any given drive at once. You could have RAID-1 where the same drive is duplicated 3 times, in which case, 3x6TB drives in a single RAID-1 still only gets you 6TB.

Personally, I run RAID-5 because when I started I only had 3 disks in my RAID. The benefit of RAID-5 (or 6 even,) is that you're still striping data across several disks so read speed will be pretty damn good (pretty close to RAID-0 performance,) but you lose performance when writing because you need to calculate and write the extra parity data. With RAID-5 you only lose 1 drive worth of storage and RAID-6 only loses you 2 drives worth of storage. RAID-5 can tolerate a single drive failure while still operating where RAID-6 can tolerate 2 drive failures.

Performance-wise, my 4x1TB WD Blacks will read at ~250-350MB/s which isn't too shabby.

Why not RAID0+1 speed and redundancy

In select cases RAID 0+1 can get you better write performance, but that's really the only benefit. You're also forced into using an even number of disks. For 4 disks, you get as many disks worth of storage as RAID-6, except you don't get nearly as much redundancy as RAID-0 in two RAID-1s could fail after a second drive failure (depending on which drives fail,) whereas any two drives in RAID-6 can fail without an issue.

The only down side of RAID-6 is not all RAID devices support it, but it's undoubtedly the best option for > 4 disks.

tl;dr: Unless you absolutely must have better write speeds, you should always go with RAID-5 or RAID-6 because it's the best balance of storage, performance, and redundancy. Even in that case, I would suggest RAID'ing SSDs if you need better performance but still need capacity and redundancy.

 

[Athlonite]

NVM miss read ya post

 

[phill]

Wrong. You always lose as least half of your storage when you use RAID-1 which literally makes it the least effective option and that's assuming you only have one copy of any given drive at once. You could have RAID-1 where the same drive is duplicated 3 times, in which case, 3x6TB drives in a single RAID-1 still only gets you 6TB.

Personally, I run RAID-5 because when I started I only had 3 disks in my RAID. The benefit of RAID-5 (or 6 even,) is that you're still striping data across several disks so read speed will be pretty damn good (pretty close to RAID-0 performance,) but you lose performance when writing because you need to calculate and write the extra parity data. With RAID-5 you only lose 1 drive worth of storage and RAID-6 only loses you 2 drives worth of storage. RAID-5 can tolerate a single drive failure while still operating where RAID-6 can tolerate 2 drive failures.

Performance-wise, my 4x1TB WD Blacks will read at ~250-350MB/s which isn't too shabby.

In select cases RAID 0+1 can get you better write performance, but that's really the only benefit. You're also forced into using an even number of disks. For 4 disks, you get as many disks worth of storage as RAID-6, except you don't get nearly as much redundancy as RAID-0 in two RAID-1s could fail after a second drive failure (depending on which drives fail,) whereas any two drives in RAID-6 can fail without an issue.

The only down side of RAID-6 is not all RAID devices support it, but it's undoubtedly the best option for > 4 disks.

tl;dr: Unless you absolutely must have better write speeds, you should always go with RAID-5 or RAID-6 because it's the best balance of storage, performance, and redundancy. Even in that case, I would suggest RAID'ing SSDs if you need better performance but still need capacity and redundancy.

So it seems I might be needing to buy 4 12Tb drives and raid them in Raid 5 (as I believe the Synology supports that without any issues and no need for extra cards etc in the system) and then just work out what I need to do with backups

I'm not sure what the 12Tb drives I'm looking at will do read/write but I have a feeling a benching session for the drives will be done when I buy them

Are there any other options I could or should consider?

 

[qubit]

Wrong. You always lose as least half of your storage when you use RAID-1 which literally makes it the least effective option and that's assuming you only have one copy of any given drive at once. You could have RAID-1 where the same drive is duplicated 3 times, in which case, 3x6TB drives in a single RAID-1 still only gets you 6TB.

Sure, but that's what I've said if you read my comment again - that he's gonna lose half his storage. He had the previous drives in raid 1, so I'm just suggesting to have the new drives in raid 1 too.
There are more options, sure, but this is the simplest and cheapest for data redundancy. There's no absolute right or wrong here.

 

[Aquinus]

Sure, but that's what I've said if you read my comment again - that he's gonna lose half his storage. He had the previous drives in raid 1, so I'm just suggesting to have the new drives in raid 1 too.

That's not a suggestion though because all he gains is more redundancy. No more storage and no more performance. Just because that's the way he did it, doesn't mean sticking with it is a good idea.

There are better options than others though and RAID-1 is literally the worst option unless you only have two drives.

So it seems I might be needing to buy 4 12Tb drives and raid them in Raid 5 (as I believe the Synology supports that without any issues and no need for extra cards etc in the system) and then just work out what I need to do with backups

I'm not sure what the 12Tb drives I'm looking at will do read/write but I have a feeling a benching session for the drives will be done when I buy them

Are there any other options I could or should consider?

If you want more storage at the cost of redundancy, go RAID-5. If you want redundancy at the cost of storage, go RAID-6 if the device supports it. If 24TB is enough storage, I would suggest RAID-6 if you're able because that's a lot of data to backup and you don't want to lose the entire array.

 

[newtekie1]

For drives 6TB and under, I say RAID5 is fine. However, for huge drives like 12TB, I'd definitely go with RAID6 if possible. The rebuild times on 12TB drives when they are pretty full is too long for my tastes, and the fear of another disk failure during a rebuild worries me too much.

Sure, but that's what I've said if you read my comment again - that he's gonna lose half his storage. He had the previous drives in raid 1, so I'm just suggesting to have the new drives in raid 1 too.
There are more options, sure, but this is the simplest and cheapest for data redundancy. There's no absolute right or wrong here.

There are some absolute right and wrong facts here though. And you are presenting wrong facts. You do not lose have your space when configured for redundancy. RAID5 and RAID6 are both redundant. RAID5 can survive 1 drive failure and RAID6 can survive 2 drive failures. With RAID5 you only lose the space of a single drive, with RAID6 you only lose the space of two drives. Not half of the storage space.

If you have more than 2 drives, RAID1 never makes sense.

 

[qubit]

@Aquinus @newtekie1 I've put a clarification on my post (post 2) so I hope that clarifies it.

 

[Aquinus]

@Aquinus @newtekie1 I've put a clarification on my post (post 2) so I hope that clarifies it.

That isn't an explanation for bad advice. Your edit doesn't invalidate anything @newtekie1 or I have said and your answer is still just as wrong.

Just raid 1 the 12TB drives and you'll be good to go.

Using RAID-6 with 6 drives literally recovers an entire disk worth of capacity and makes the array more tolerant of failure. There is no justifiable reason for using RAID-1 with 6 disks.

 

[phill]

That's not a suggestion though because all he gains is more redundancy. No more storage and no more performance. Just because that's the way he did it, doesn't mean sticking with it is a good idea.

There are better options than others though and RAID-1 is literally the worst option unless you only have two drives.

If you want more storage at the cost of redundancy, go RAID-5. If you want redundancy at the cost of storage, go RAID-6 if the device supports it. If 24TB is enough storage, I would suggest RAID-6 if you're able because that's a lot of data to backup and you don't want to lose the entire array.

I'd be adding either a Raid 1 volume with two drives and one for backup or I'd consider 3 or 4 new drives for a completely new volume and start a fresh using another Raid model.

I believe the only reason why I set up a Raid 1 over any other Raid, was that I never had enough disk space to backup everything to so now is why I'm considering a completely new Raid setup on the NAS I'll probably still end up having to buy more drives again to make sure I have enough backup space but that's another thing extra that I'd do personally.

For drives 6TB and under, I say RAID5 is fine. However, for huge drives like 12TB, I'd definitely go with RAID6 if possible. The rebuild times on 12TB drives when they are pretty full is too long for my tastes, and the fear of another disk failure during a rebuild worries me too much.

There are some absolute right and wrong facts here though. And you are presenting wrong facts. You do not lose have your space when configured for redundancy. RAID5 and RAID6 are both redundant. RAID5 can survive 1 drive failure and RAID6 can survive 2 drive failures. With RAID5 you only lose the space of a single drive, with RAID6 you only lose the space of two drives. Not half of the storage space.

If you have more than 2 drives, RAID1 never makes sense.

I think I might have made a mistake or misjudgement that I should have considered a different Raid model but at the time and still now I just about have enough storage space to make sure I have everything completely backed up as I mentioned just above

I believe @qubit isn't wrong as such, he's just agreeing that another Raid 1 would be the easiest thing to do.
With that said if I'm going to completely take out the 3 Raid 1 volumes I have altogether, I'll consider using a new model of raid as I have so many drives and with the added fact I'm going to replace those 6 drives with possibly 4 new ones of bigger size, I will be in a better position. That said, I just need to make sure that I have physically enough storage space to be able to backup everything I have, otherwise if anything happens to any thing, I'd have lost it if the worst happens. I can't have that with my personal data

That said, now being in IT I'd hope I wasn't that silly to make a daft error and loose it all as well!

 

[qubit]

@Aquinus I don't see where I went wrong to be honest and suspect a comms error somewhere, lol. Anyway, at work now, so I'll have a look properly at both your comments and @newtekie1 later and reply then to try and clear this up.

 

[phill]

@Aquinus I don't see where I went wrong to be honest and suspect a comms error somewhere, lol. Anyway, at work now, so I'll have a look properly at both your comments and @newtekie1 later and reply then to try and clear this up.

Hopefully also my reply above will help clear up some of it as well. No wrong answers here, just more educated answers lol

 

[newtekie1]

@Aquinus I don't see where I went wrong to be honest and suspect a comms error somewhere, lol. Anyway, at work now, so I'll have a look properly at both your comments and @newtekie1 later and reply then to try and clear this up.

You're only right if you assume he is only using 2 drives. I read the original post as he was going to be using 6x12TB drives.

 

[Deleted member 67555]

I guess it really depends on the importance of the data but maybe try just doing a weekly backup of new files.
Unless it's for business do you really need daily redundancy?

 

[Ahhzz]

I'm a RAID 5 +1 myself. Raid 5 for the security of a single drive failure not losing data, and then the +1 being a hot spare that gets pulled in ASAP if something goes wrong. Best tradeoff for redundancy with minimal loss of space, imo

 

[phill]

I guess it really depends on the importance of the data but maybe try just doing a weekly backup of new files.
Unless it's for business do you really need daily redundancy?

I only tend to run a backup process every week or two, but I just like to make sure if I have changed a lot in a few days or gone through it and deleted all duplicates, that I'd do it right away.

The raid 5 idea sounds like a good way of maximising space but the plus 1 also helps just in case there's a failure. Is that simply called Raid 5+1 or is it Raid 6?

How would you set that up? I'll have to have a Google and see if Synology would even support it.. Either way, I'm thinking 4 or 5 new drives and then equal the space to make sure I can backup the complete load of data

 

[Ahhzz]

I only tend to run a backup process every week or two, but I just like to make sure if I have changed a lot in a few days or gone through it and deleted all duplicates, that I'd do it right away.

The raid 5 idea sounds like a good way of maximising space but the plus 1 also helps just in case there's a failure. Is that simply called Raid 5+1 or is it Raid 6?

How would you set that up? I'll have to have a Google and see if Synology would even support it.. Either way, I'm thinking 4 or 5 new drives and then equal the space to make sure I can backup the complete load of data

Not sure about Synology support, but a Raid 6 is not a 5+1. Raid 6 just adds an additional drive as parity, so you lose 2 drives worth of space instead of just 1. In reality, it pretty much does the same thing, but in my head, 5+1 gives me a drive sitting there, not generating read/write cycles and additional usage for failure, whereas a Raid 6 is using all those drives all the time, so more chance for failure.

 

[newtekie1]

RAID is complicated, LOL. RAID5+1 is different from RAID5 + Hot Spare which is different than RAID6. I'll explain.

RAID5+1 is a nested RAID where you have two RAID5 arrays, that are then mirrored in a RAID1 array. It's never really used.

RAID5+Hot Spare is a standard RAID5 array, with an extra hard drive connected to the RAID controller designated as a Hot Spare. So in the event of a hard drive failure in the RAID5 array, the Hot Spare is immediately used to rebuild the array. This is not RAID6, because during the rebuild, if you have another drive failure, you data is lost.

RAID6 is double parity. Two drives are used to calculate parity, if one fails the array is still redundant. Even if a second drive fails, your data is still intact.

If you just look at the differences between RAID5+Hot Spare and RAID6, ignoring RAID5+1 because no one really uses that, the easiest way to explain it is what happens when a drive fails in each. With RAID5+Hot Spare when a drive fails, the array effectively becomes a RAID0 array until the rebuild process is completed. With a RAID6 array when a drive fails, the array effectively becomes a RAID5 array.

 

[theonek]

well, if you need only speed, and have other more secure place to hold the files, you can easily make raid0 and enjoy the limit of sata interface like this....

 

[phanbuey]

Raid 1+0 or raid 6 seem like the best options. We always set our SANs up with raid 10 w/hot spares. but the san has like 48 disks in it and it's tuned for maximum IOPS. Not sure if it would be economical with 6 drives but the performance is great. And if a drive fails, there is still likely a working mirror drive in the raid 0 array to rebuild the hotspare.