I recently picked up an older Dell PowerEdge for a home lab and plan to run a hypervisor such as Proxmox, Nutanix, or CloudStack, although I have not chosen one yet. Before buying disks, I want to choose a storage layout that balances cost, reliability, and performance, with cost being the biggest factor. Ideally, I would start with the smallest practical number of drives and add more over time. Critical data will be backed up to a NAS. Is RAID 1 unnecessary for this use case, and what configuration would be easiest to expand later while still providing reasonable protection and VM performance?
4 Answers
Treat the operating system and VM storage as separate needs. A small mirrored pair is a sensible place for the hypervisor installation, while the VM datastore can use RAID 10 or a ZFS mirror-based layout. RAID 10 gives good VM performance and lets you expand by adding additional matching mirror pairs, but only if the controller or storage system supports that kind of expansion. Do not assume every hardware RAID controller can grow a RAID 10 array safely.
There is no single best RAID level without knowing the drive type, number of bays, controller, and workload. RAID 10 is generally a strong choice for VM storage on hard drives because random-write performance and rebuild behavior are better. RAID 5 can be acceptable for a small, mostly-read lab with limited disks, while RAID 6 becomes more attractive for larger arrays or when using many disks. SSDs can make parity RAID more practical, but they do not eliminate the need to check controller support.
Start by checking the exact PowerEdge model, PERC controller, number of drive bays, and whether the controller supports passthrough or online expansion. Also remember that RAID is not a backup. If the budget only allows two drives, a mirrored pair is safer than a single disk, and you can keep the NAS backups for recovery from deletion, corruption, or a larger hardware failure.
If you use ZFS, put the Dell controller into HBA, IT, or passthrough mode so ZFS can access the disks directly. For a small lab, mirrored vdevs are usually easier to manage than trying to build a large array immediately. Check drive compatibility first, though: consumer disks may behave poorly behind some controllers, and ZFS needs reliable access to drive health information.
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