Replace SSDs with HDDs

[aGraphicz]

Hi there

1 year ago I bought a DS920+ with 4 SSDs from Seagate. Slowly I am realizing I made a mistake when buying it, for one simple reason: NAS SSDs are insanely expensive and hard to find.

The SSDs are 1.92 TB each and for the amount of data I need they are not enough (I am using SHR). Now, I would like to replace them with 4 NAS HDDs (Seagate Ironwolf) of 4TB each.

As I am switching from SSD to HDD, do I risk to lose some data?

I have 2 backup copies (using USB Copy), but still I don't want to rebuild everything again. So my idea was like to simply replace and extend the Storage Pool.

Many thanks for any hints!

 

[Lewis]

In theory, if you replace one by one and let it run it's thing of raid rebuilding after each replacement it should work fine without any loss of data. I recently replaced 8*8TB for 8*14TB bud die big amount of data and SHR-2 mode it took few weeks to finish all (cca 60-70h per disk) but your disks are much smaller and it's only 4 drives so i guess you could be done in few days.

 

[aGraphicz]

In theory, if you replace one by one and let it run it's thing of raid rebuilding after each replacement it should work fine without any loss of data. I recently replaced 8*8TB for 8*14TB bud die big amount of data and SHR-2 mode it took few weeks to finish all (cca 60-70h per disk) but your disks are much smaller and it's only 4 drives so i guess you could be done in few days.

Thanks for your answer.

I have a total of 3TB on my SSD's. You think it's gonna take days when I replace the disks?

 

[Lewis]

Hard to know but it depends on speed of new disk and how long it'll take to rebuild the array, if you have DSM 7.x it should be faster. I'm on DSM 6.2x and lot more data so for me to replace 8TB into 14TB took a lot of time and i had to do it 8 times one by one .

So just to recap you have to do this ONE by ONE, so replace one disk and wait until all is rebuilt and volume is repaired 100%, then yo go to next drive in line. In no circumstances do this on 2 drives or more at once.

Volume size was extended for me automatically after each drive step by step...

 

[aGraphicz]

Hard to know but it depends on speed of new disk and how long it'll take to rebuild the array, if you have DSM 7.x it should be faster. I'm on DSM 6.2x and lot more data so for me to replace 8TB into 14TB took a lot of time and i had to do it 8 times one by one .

So just to recap you have to do this ONE by ONE, so replace one disk and wait until all is rebuilt and volume is repaired 100%, then yo go to next drive in line. In no circumstances do this on 2 drives or more at once.

Volume size was extended for me automatically after each drive step by step...

Got it, thanks

I am also on DSM 6.2x ...

You think I should upgrade to 7.0 before changing from SSD to HDD?

 

[Lewis]

I'd keep it as is for now, or upgrade to 7.x and use it few days to be sure all is ok that way. Depends on your need really.