Question Adding last 2 discs to 4-bay NAS

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Question Adding last 2 discs to 4-bay NAS

Adding those disks will require no changes and leave you with a RAID5 equivalent when all is done. Assuming the disks are the same size, your overall capacity will increase by the size of one new disk.
 
SHR mimics RAID1 for the first 3 disks
Surely SHR mimics RAID 1 with 2 disks, and then RAID 5 for 3 and more disks. SHR2 starts mimicking RAID 6.

@wwwampy this is the Synology explanation of why they think SHR benefits 'normal' users (that'll be me) when using disks of different size in the same array
https://www.synology.com/en-uk/knowledgebase/DSM/tutorial/Storage/What_is_Synology_Hybrid_RAID_SHR

Other info on the RAID types, which is pretty obvious if you've had a NAS for a while
https://en.wikipedia.org/wiki/Standard_RAID_levels#RAID_1
https://en.wikipedia.org/wiki/Standard_RAID_levels#RAID_5

This is an interesting explanation of how RAID 5 can lose any 1 disk and recreate the data from the remaining blocks: Parity bit - Wikipedia
 
So if you have a 4-bay machine with 2 bays populated, and you want to populate the remaining 2 bays with disks which are identical in size to the original 2 disks (so you end up with 4 identical disks), and you're running SHR, and want to enlarge the existing volume (rather than creating a second volume) do you add the two disks at the same time, or add one, and then the other?
 
I can't try it, but I would expect that Storage Manager will dictate the available options, meaning: physically adding disks can be done and they will appear in SM's HDD/SSD page but then in Storage Pool the action is Add Drive, not Add Drives. So SM should either deny or allow multiple disks to be added at the same time, but it should tell you or grey-out the options.

My hunch is that only one disk at a time can be added to the pool, even if both are physically loaded into the NAS.
 
So if you have a 4-bay machine with 2 bays populated, and you want to populate the remaining 2 bays with disks which are identical in size to the original 2 disks (so you end up with 4 identical disks), and you're running SHR, and want to enlarge the existing volume (rather than creating a second volume) do you add the two disks at the same time, or add one, and then the other?
You can do it both ways. Adding one at a time will expand the volume twice, needless if you want to use both od the remaining drives. Just add them and expand
 
Confirming - Rusty is absolutely right (of course...) - I added two new disks to the two empty bays in my 4-disk 918+, and it permitted me to add them both to the volume simultaneously. Of course, "expanding" the volume is (as expected) taking forever.
 
I’ll be waiting for the 2020 modules and upgrade to four bays.
It’s rumored that it’ll have four 5.25" floppy drive bays with an option to install one 3.5" drive in the special drive bay for caching if you're a power user who wants to push it to the limit (must be scary at the limit, be careful). The CPU will be the upcoming state of the art nano-shell clam running at 25 gigameters/hour with red Brembo brakes as an option.

Networking will be provided by a special, dual self-balancing RJ-11 module using an advanced algorithm on an ASIC chip written by a boiled egg.
 
It’s rumored that it’ll have four 5.25" floppy drive bays with an option to install one 3.5" drive in the special drive bay for caching if you're a power user who wants to push it to the limit (must be scary at the limit, be careful)
In which case I'll wait for 2021 which rumour has it will be supporting 20MB Bernoulli drives. By 2025 there'll be expansion support for Zipp and Jazz drives.
 
Signs you're getting old: when you start referencing Zip drives and 5.25" disks in your messages :)

I still have a shoebox half full of Zip disks.
My wife asks me why do I keep them.

Because I might need what's on them.
What's on them?
I don't know.
If you don't know then you don't need them.
How do you know?!
I don't know.
There you go, makes two of us. We BOTH need them!
 
Dietzgen_B-1725_LarryKehl.jpg
 

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