Is it possible to enable RAID 1 on an already in-use HP Proliant DL380 G5

I have a HP Proliant DL380 G5 with two HDDs in RAID 0 (Stripe)(72GB+72GB). It has been running Windows Server for quite a while now and has 30GB of occupied space on a stripted volume.

I've now purchase two 72GB HDDs more (same as the one's already installed in the server). I'd like to make that system more safe by introducing HDD mirroring of the existing striped disk.

1. Is it possible to create a RAID 1 (mirror) on a disk that has already been in use?
2. Is it possible to mirror a striped disk pair?

Thanks in advance.

Yes, this is possible.

See: Can I convert a 1 disk RAID 0 to RAID 1?

You're lucky that your striped array has worked until now. The process you'll go through is an "array transformation".

• Make sure your system has a battery-backed cache (BBWC) on the RAID controller.
• Add two more disks of equal or greater size than the existing disks.
• Install the HP Smart Storage Administrator (HPSSA) software for Windows (or the HP Array Configuration Utility is this is an old version of Windows).
• In the software, add the two new drives to the existing array.
• In the software, perform an array transformation from RAID0 to RAID 1+0.

I know this is way late for the OP but good advice nonetheless - BACKUP BACKUP BACKUP! Don't tinker with anything with the filesystem, RAID configuration, etc.. without backing it up first, especially with a RAID0! Also, RAID is not a substitute for a good backup, even though most of the time if a single disk fails you can rebuild the array without error/downtime, if you have a multiple disk failure, or if power is interrupted whilst the array is rebuilding, your only solution may be restore from a backup.

Should your controller not support an array transformation, you may be able to transform it using CloneZilla (www.clonezilla.org), the key is if the array shows up as a device vs if it shows the individual disks in the array (Some "FakeRAID" type controllers do this; on my HP system the SATA RAID controller shows each disk where the SAS RAID controller presents the array as a block device). If it shows the array as a block device, you can clone the disk to an external or spare hard drive, then after verifying it's correctly cloned, rebuild the array from scratch with the new configuration, and then restore the cloned image back to the array.