Replacing 1.5 TB drive with 4 TB took 10 hours for 4.5 TB used on 5.5 TB SHR array
- information collection
- max supported storage: 16 TB (4 TB in each 4 bays)
- latest DSM version: 6.0 is out (I postponed to update after replacing HDD)
- RAID calculation: existing 1.5+2+2+2 = 5.5 usable to 2+2+2+4 = 6TB usable (SHR1)
- determining HDD brand: WD Green & Seagate Barrucada available and I chose Seagate as WD green’s head parking cause problem for NAS
- SMART attribute: I have non-zero nubmers under Reallocated Sector Count & Drive Reconnection Count & and everyone suggested Reallocated Sector Count should be zero (and if non-zero, backup data and replace ASAP)
- getting compatible disk model – check this page before buying
- deciding which HDD size to buy (using RAID tools) – this calculator can show how much disk space will be used or unused (make sure to read instruction before you buy HDD)
- reading instruction – Synology KB has complete instruction on how to perform. Left it open to read while you are performing the steps.
- buying – bash out the money, check physical defect and warranty period
- physically replacing – note which bay to eject, shutdown, eject bay, replace HDD, insert bay, restart, then disable beep (if beeping)
- repairing – inserted HDD is uninitialized. Initialize and repair the volume group.
- expanding – depending on the size of newly inserted HDD, you might need to expand the volume. Mine can expand another 500GB. It took less than 1 minute to expand.
- pricing calculation 44 MMK/GB
Other things I learnt
- SMART Value means normalized Value and it should be greater than Threshold number
- For reallocated sector count, not only the number but also the rate of increase in number is important.
- I had 2 (out of 4) HDD having non-zero reallocated sector count.
- 1.5TB with lower number but much higher power on hour
- 2TB with much higher (4 digit within 4 months)
- Contrary to theory I learnt, I changed the 1.5 TB with 4TB. Now I am running with those 4 digit sector count.
- SHR1 can accept one drive failure
- SHR2 can accept two drive failure
- make sure you use Uninterruptible Power Supply during repairing