I manage the media archival server for a small photography and graphic design business. We use a five-bay Synology DiskStation 1512+ to archive completed projects and to store TimeMachine backups. I have rebuilt the array a couple of times over the years to replace failing disks and to increase disk size, and I am concerned that my original RAID configuration is no longer appropriate.
The array currently has five new Seagate Ironwolf 3TB disks (ST3000VN007) in a single SHR volume (essentially RAID 5), and it’s my understanding that RAID 5 is insufficient for disks of that size, even with regular data scrubbing. I have a current backup that I can use to rebuild the array, and the volume is currently less than 25% full so there’s a lot of room for extra redundancy. As the server is primarily used for archival, I care mostly about reliability, cost, and ease of maintenance & repair.
What are my best RAID options for a five-bay Synology DiskStation? I could simply continue to use SHR and rely on backups if a resilvering ever fails. I could rebuild the system with SHR-2 (or RAID 6) for an extra disk of redundancy. I suppose I could also switch to RAID 10, but what would I do with the odd disk, a warm spare? How should I weigh the options, and how can I minimize the risk of data loss? The DiskStation does not support conversion of SHR to other RAID types, so I would need to restore from backup to switch.