Hi! I have 3 disks (36 GB SCSI) in RAID 5 (hardware RAID) and the space on volume is almost full. I need more space and I want to add one more disk to this array. Can I add a disk without lose the information on the volume? Thanks!

This is a bit complicated but I will try to keep it simple. If your hardware raid controller supports dynamic restriping, yes you can add a drive or drives to the raid5. This does not mean it adds that space to the volume. I will get to more on that in a second. If your raid controller does not support dynamic restriping the only way to add disks to the raid5 is to wipe the array and restrip with the extra disk(s). This means a backup and reinstallation of the OS then a restore from that backup of OS and data. Now let's say your raid controller can restripe dynamically. Afterward when you go into Disk Manager you will see your regular volume AND available space. After all the OS has no way intuitively of adding that space to the end of the last volume. Here is where you have a hard choice and it depends on how you setup the partitioning/volumes. If you have a data partition and the disk is dynamic you can create a volume set to add in the additional space. I consider this common practice a TERRIBLE solution. Since a volume set has no fault tolerance you literally creat a non fault tolerant volume on a fault tolerant raid array. This means if you lose the volume set pointer [chkdsk error/system crash] you lost EVERYTHING with no recovery. You are only as good as your last backup. Kinda defeats having a raid array doesn't it? Recommendation is to take the additional free space and create another partition/volume and use it that way. Give a person a fish, they eat for a day. Suggest they internet search and they learn a skill for a lifetime.