Quick answer: RAID is selected as the disk & RAID option when ordering — the array is built during provisioning. RAID 1 (mirror) is the safe default for two disks; RAID 10 combines speed and redundancy on four; RAID 0 is fast but has zero fault tolerance. Changing the RAID level later requires a reinstall, so decide before loading data.
Overview
RAID combines physical disks into one logical volume for redundancy, performance or both. On dedicated servers it is either hardware RAID (a controller manages the array, transparent to the OS) or software RAID (Linux mdadm/ZFS manages it). Remember: RAID is not a backup — it protects against disk failure, not against deletion, ransomware or fire.
Before you start
- Know your priorities: capacity vs redundancy vs speed.
- Disk count and types in your configuration (levels need minimum disk counts).
- A separate backup plan regardless of RAID level.
Step-by-step guide
- Pick the level:
- RAID 0 (2+ disks) — full capacity and speed, any disk failure loses everything. Only for reproducible data.
- RAID 1 (2 disks) — mirror; half capacity, survives one disk failure. Default for system disks.
- RAID 5 (3+ disks) — capacity-efficient with parity; survives one failure; slow rebuilds on large HDDs.
- RAID 10 (4+ disks) — striped mirrors; fast and redundant; best for databases.
- Select it in the disk & RAID option when ordering, or state it in your custom configuration request.
- After handover, verify the array: software RAID —
cat /proc/mdstat; hardware RAID — controller CLI (storcli,MegaCli) or ask support for the controller model. - Add array state to your monitoring — a degraded array that nobody notices defeats the purpose.
Common issues
- Treating RAID as backup: it is not — replication of a deletion is instant on all mirrors.
- RAID 5 on huge HDDs: rebuild windows can stretch to days with degraded performance — prefer RAID 10 for busy arrays.
- Wanting a different level after go-live: that is a reinstall — plan it as a reinstall request with a full backup.
When to contact support
Open a ticket to confirm which controller your configuration uses, to get a failed disk replaced (SMART/controller errors), or to schedule a RAID-level change with reinstall.
Frequently asked questions
Which RAID level should I pick?
RAID 1 is the safe default for two disks; RAID 10 on four disks adds speed while keeping redundancy. Use RAID 0 only for data you can afford to lose completely.
Can I change the RAID level later?
Yes, but changing the RAID level requires a full reinstall and wipes all data on the disks. Plan it as a scheduled reinstall with a verified backup taken beforehand.
Does RAID replace backups?
No. RAID only protects against physical disk failure — deletions, ransomware and human errors replicate to all mirrors instantly. Keep separate off-server backups.
Related articles
- How to request OS installation or reinstall
- How to monitor dedicated server performance
- How to request hardware diagnostics
- How to order a dedicated server
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