Raid 5 question

[ingeborgdot]

I have an older model of a Synology NAS. 1010+ 5 bay. I am using Raid 5.
I have added two new HDD and each was 2TB (1.863TB) more for a total of 4TB (3.726TB). I have a total of 14TB of HDD but it says that I only have 7.2TB in Storage Manager. What am I doing wrong? Am I just wasting money adding another HDD? I need more space so I am adding larger HDD.

 

[L&LD]

It seems about right to me.

http://www.raid-calculator.com/default.aspx

 

[ColinTaylor]

I need more space so I am adding larger HDD.

This is where you've gone wrong. With RAID5 the usable space on each disk will be limited to the capacity of the smallest disk in the set.

Either create a separate RAID1 volume from your new disks or see if the Synology supports some sort of hybrid format that will allow you to use the entire capacity as a single volume.

EDIT: I'm not a Synology user but this post suggests there's something call SHR that might do what you want.

https://www.synology.com/en-us/knowledgebase/DSM/tutorial/Storage/What_is_Synology_Hybrid_RAID_SHR

 

[dosborne]

With the HDDs that you have, you need to decide if you need the RAID capabilities at all or not. Are you running RAID because "you can" or because you want the redundancy?

If you don't need the redundancy, then you could migrate the data to single volumes or a conglomerate volume, but be aware of the risks. If you go to a single volume, you maximize capacity, but a single drive failure would mean the loss of all data (so have a backup - RAID is *NOT* backup).

Ideally, if you are running RAID, you want all of your HDDs to be the same capacity, and to be "NAS" drives (WD Red, Seagate Ironwolf, etc). Not an absolute requirement, but something to consider.

As mentioned above though, in most cases (not sure about your model specifically) you could mix and match essentially keeping your "old" RAID system in place and add the "new" drives as single volumes, a volume set or mirrored drives.

 

[ingeborgdot]

Well, it is too late to switch from the Raid 5. What I need to do is replace the smaller drives with 4tb drives and I will get the volume that I need. I never realized that the discs needed to be the same size to make it all work properly. Thanks for the help.

 

[ingeborgdot]

Actually, after looking at the whole picture, I am going to replace my old NAS which is now over 10 years old and has not been supported now for almost 2 years now. My Synology 1010+ is EOL a couple of years ago. It is a nice NAS but it is too important of a piece to our documents, videos, etc. to chance it. I will just use this as a backup to the new NAS which is a backup to the stuff on our computers.
Now, on to some research to find the best NAS for us. Probably looking at another Synology or a QNAP.
I have worked with this for many years but just never paid much attention to the size of the HDD. I guess size does matter. But at least now, I have a little bit more common sense with Raid 5 and different size HDD that work.
I may try their own Raid setup that is a little more space saving friendly.

 

[degrub]

a NAS is not backup. It is intermediate storage for files you need to access. You are vulnerable to a NAS hardware failure. In many cases, the only way to recover your files is to have the exact same hardware and firmware on a second NAS, in your case two 1010+ boxes.

You need an independent backup disk for the NAS connected by the fastest I/O available on the unit. Use a disk format that is compatible across OSs - windows, mac, linux that you use so that you can just plug it into another PC and recover the files if the NAS ever fails.
Have two copies for insurance. If the files really are important consider offsite or cloud storage as well.

 

[L&LD]

@ingeborgdot what I normally suggest is to leave the currently running NAS alone when they are up for replacement/updating. Buy a new NAS, COPY the data to the new NAS, verify it works properly for a few weeks.

Now, upgrade the drives on the old NAS to the maximum it can support. This will take a long time with 5 drives. When all drives have been fully updated on the old NAS, use it as a backup to the new NAS. Test regularly (weekly or more often) that the data it contains is still readable and not corrupted too.

 

[ingeborgdot]

@ingeborgdot what I normally suggest is to leave the currently running NAS alone when they are up for replacement/updating. Buy a new NAS, COPY the data to the new NAS, verify it works properly for a few weeks.

Now, upgrade the drives on the old NAS to the maximum it can support. This will take a long time with 5 drives. When all drives have been fully updated on the old NAS, use it as a backup to the new NAS. Test regularly (weekly or more often) that the data it contains is still readable and not corrupted too.

That is exactly what I'm planning on doing.

a NAS is not backup. It is intermediate storage for files you need to access. You are vulnerable to a NAS hardware failure. In many cases, the only way to recover your files is to have the exact same hardware and firmware on a second NAS, in your case two 1010+ boxes.

You need an independent backup disk for the NAS connected by the fastest I/O available on the unit. Use a disk format that is compatible across OSs - windows, mac, linux that you use so that you can just plug it into another PC and recover the files if the NAS ever fails.
Have two copies for insurance. If the files really are important consider offsite or cloud storage as well.

Your solution is not as safe as having 2 NAS, which is what I am doing. Having it on 2 NAS will be a much safer option than just a single drive since both NAS will have redundancy. I understand that Raid 5 is not a backup, but it is a much safer option than just having all of your stuff on one HDD or another backup up of that drive on another single HDD as there is no redundancy. And you see with my sentence structure, I believe in being redundant.

 

[coxhaus]

In a type RAID 5 even if you upgrade all the drives to a larger size you will not see the bigger drives until your rebuild the RAID5. So that means you need to copy all the data off to somewhere and rebuild the RAID 5 to the larger drive size. Then copy all the data back to the new RAID 5. RAID 5 is N-1 where the extra drive is a parity drive. You can only stand to lose 1 drive, any more drives fail after 1 drive the RAID 5 fails.

 

[dosborne]

In a type RAID 5 even if you upgrade all the drives to a larger size you will not see the bigger drives until your rebuild the RAID5. So that means you need to copy all the data off to somewhere and rebuild the RAID 5 to the larger drive size. Then copy all the data back to the new RAID 5. RAID 5 is N-1 where the extra drive is a parity drive. You can only stand to lose 1 drive, any more drives fail after 1 drive the RAID 5 fails.

Actually, that isn't always the case. It is likely the easiest and best approach, but with some manufacturers, it is possible to upgrade the HDDs one at a time until they are all "larger" than the original RAID 5 volume, then increase the volume size A time consuming process as you have to rebuild the raid array after each HDD change.

These days, doing any amount of work for 2TB-4TB drives seems like a waste of time. I like @ingeborgdot's idea of just getting a new NAS and new HDDs. My advice is get as large a drive as you can afford with a minimum of 2x as a starting point and increase the number when possible. Although I prefer a 5-bay unit myself, in this case a 2-bay unit may provide enough capacity and redundancy for your needs allowing you to spend less on the enclosure and more on the drives themselves.

 

[ColinTaylor]

In a type RAID 5 even if you upgrade all the drives to a larger size you will not see the bigger drives until your rebuild the RAID5. So that means you need to copy all the data off to somewhere and rebuild the RAID 5 to the larger drive size. Then copy all the data back to the new RAID 5. RAID 5 is N-1 where the extra drive is a parity drive. You can only stand to lose 1 drive, any more drives fail after 1 drive the RAID 5 fails.

Not necessarily. I don't know about Synology but the RAID systems I've used allow you to expand the volume size, after which you can "grow" the filesystem.

 

[coxhaus]

Actually, that isn't always the case. It is likely the easiest and best approach, but with some manufacturers, it is possible to upgrade the HDDs one at a time until they are all "larger" than the original RAID 5 volume, then increase the volume size A time consuming process as you have to rebuild the raid array after each HDD change.

These days, doing any amount of work for 2TB-4TB drives seems like a waste of time. I like @ingeborgdot's idea of just getting a new NAS and new HDDs. My advice is get as large a drive as you can afford with a minimum of 2x as a starting point and increase the number when possible. Although I prefer a 5-bay unit myself, in this case a 2-bay unit may provide enough capacity and redundancy for your needs allowing you to spend less on the enclosure and more on the drives themselves.

Sounds dangerous to me rebuilding the RAID that much. Yes a large mirror might work. But read speed off of a 5 or 8 drive RAID 5 is hard to beat.

 

[coxhaus]

Not necessarily. I don't know about Synology but the RAID systems I've used allow you to expand the volume size, after which you can "grow" the filesystem.

I want to say Adaptec RAID cards, DELL RAID cards, IBM RAID cards and Intel RAID cards had this ability. They used containers not drives. It allowed more flexibility .

 

[abailey]

If you are going to purchase a new NAS or rebuild your current one I would certainly not go with RAID 5. In fact I abandoned RAID 5 about 10 years ago as it becomes more and more dangerous to use for fault protection as hard drives get larger in capacity. You can Google Raid 5 and see many articles on it if you are not aware. He is a link to one example: https://www.digistor.com.au/the-latest/Whether-RAID-5-is-still-safe-in-2019/

 

[coxhaus]

I have heard the same thing. All my RAID building was many years ago on smaller drives. I have used all the RAID cards above many times building RAIDs but I have not used really large drives in RAIDS.

 

[dosborne]

In fact I abandoned RAID 5 about 10 years ago as it becomes more and more dangerous to use for fault protection as hard drives get larger in capacity.

While some scenarios may seem riskier, if you acknowledge that raid is not backup, then there are definite advantages to using it with the proper equipment to mitigate failure.

 

[Mark070]

On Synology, I use the SHR-2 on a 5 bay model. I know its not a direct answer - but, if you have drives and eventually want to make more space without buying new everything .. use the SHR-1 or SHR-2, and add as you need.

Copy off existing data from your Raid5 onto a back up, rebuild using SHR-1, and copy back. If you want more space using a bigger HD, than just replace an existing drive.