Safely remove all disks of a synology NAS while its turned off

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I have a Synology 4-bay NAS (RS409RP+) with a RAID 5 installed on 4 hard disks. Now I need to upgrade the NAS to a bigger set of hard disks, and because these hard disks are 3TB each, I cannot use the normal RAID upgrade function. Of course I am going to make a backup and migrate the data over to the new disks, but I would like to keep the old disks functioning in the meantime, so if something goes wrong, I can reinsert the old four disks and continue as normal.

My question is, when I shutdown the Synology NAS and remove ALL of the disks, is it possible to re-insert them again later in the same order and will they still function normally?

Or does the NAS keep some information about the internal hard disks somewhere else (e.g. in the bios or an internal flash memory) and will it report that the raid has failed when I insert the old disks again? Or will it know that I have inserted some other disks in the meantime?

According to my understanding it shoud be save, but before I attempt this, I would like to know if someone has some definitive experience with this?

Best Answer

Yes, I have done this. At least, I have removed all the drives, and put them back in, and powered up without data loss. I have not swapped drives in the middle.

Related Solutions

Setting up a RAID 5 with expansion in the future in mind

Instead of a single boot disk and 3 disks in RAID 5, consider 4 disks in RAID 10. This is both faster and safer. You do not want your NAS to go down if the single boot disk fails. Additionally, RAID 5 has poor write performance and does not rebuild reliably on large, terabyte-denominated volumes, especially when you are using inexpensive drives.

Answers:

Replacing a disk with a larger one: Not with a standard RAID controller. Some vendors (e.g. Drobo) have proprietary RAID implementations that support adding disks of dissimilar sizes, etc., but traditional RAID remains far more dependable. If you want to play with something dynamic and innovative, I would suggest ZFS. Added in response to TomTom's observation that only half of question #1 had been answered: Expanding an array by adding disks of the same size as existing array members is supported by many enterprise RAID controllers. Larger disks will be treated as though they are no larger than existing disks. This may be unsupported by low-end/integrated RAID devices. Check the documentation for your specific controller.
No. RAID is never an excuse for failing to have a backup and a DR plan. Having "too much data" is also not an excuse for failing to back up; however, it may be an opportunity to assess whether any significant portion of your data can be classified as genuinely unimportant.
With consumer grade 2TB SATA drives costing only $80 each in 2011, and enterprise-grade 2TB SAS drives costing only $240, you can add 4TB of usable RAID 10 capacity for $320 (consumer-grade) or $960 (enterprise-grade) if you have sufficient bays and connectors. That's a very cheap incremental upgrade path.

Best RAID config for Data Backup NAS

What RAID is best for data recovery?

That depends on your use case. It depends whether you want more redundancy, more storage capacity or more performance. See this overview for more information about the specific levels.

Am I able to just pull a drive out with all the data on for an easy off-site backup? Would obviously replace this with a new fresh drive.

This depends on the RAID level.

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