Once upon a time, I was taught to spread an order among at least two retailers whenever I needed around six or more hard drives, and three when the order gets up around 20 drives or more. Use the same make and model of disk, but source them from different places (this was back when raid cards would only work right if all the disks matched exactly). When installing the disks, make sure each RAID array has a mix of disks from each of the sources.
The purpose here is to prevent problems if the there's a bad lot of disks and the vendor just adds them to your shipment sequentially. This could result in multiple disks in the same RAID arrays failing at near the same time, which could mean data loss.
Is this still good guidance, or are most reasonable enterprise vendors (ie: not newegg, tiger direct, or amazon, that deal mainly with consumers) aware of the situation and now deal with it correctly? Is it dealt with at the manufacturer level (manufacturing runs are broken up before vendor delivery)? Is it something you have to ask for? Or am I just worrying too much?
Best Answer
Disks fail, and you typically want to get them from different batches to be safe. Once you get them you still want to run them for a few days or weeks to be sure to shake loose the problem disks.
I've had disks go bad as quickly as one or two days before (EMC disks) and I've had the same disks from that array last for years. To be safe I would mix and match or if you need to order from the same vendor spread the order out over a month or two so you get disks from different batches.
Am I insanely paranoid when it comes to disk failure? Yep sure am. Nothing worse than losing data.