0

Specs for some RAID controllers (for instance LSI 9261-8i) say that it's possible to mix SAS and SATA disks in the same RAID array but such practice is discouraged (but without explanations why). There was mention here on SF that some admins use such mix to minimize cost(on software RAID, my case is hardware RAID). What will be consequences or drawbacks of such mix?

Mark Smirnov
  • 13
  • 5

2 Answers2

1

but such practice is discouraged (but without explanations why)

Most RAID controllers run better when HDDs are close to each other in speed. Different models/interfaces break that. Many controllers don't even permit arrays with mixed drives (by grade or interface).

Be prepared that any enterprise-grade drives don't speed up an array made up of nearline or consumer-grade disks. In other words, your array performance is likely determined by the slowest drive.

Zac67
  • 10,320
  • 2
  • 12
  • 32
  • I completely agree. I have several arrays for different purposes: RAID 0 for speed consist from the same model fast SAS HDDs. For capacity purposes I'm going to mix different HDDs - because of shortage of supply I enforced to use mix. I use RAID controllers to connect lots of HDDs and I will prefer IT mode or HBA to avoid creating RAID 0 because I's easy to lost data. I don't want redundant RAID 5, 10, etc (loosing ~30%). Will backup files on streamer. – Mark Smirnov May 08 '21 at 01:04
0

Do whatever is convenient and financially affordable for you. Always keep good backups. Try always to configure your RAID to handle one extra fault (one more than you expect statistically). Buy good-quality disk drives that are relevant for your workloads, maybe even follow advice from the disk vendor (don't use consumer drives in a big NAS, don't use NAS drives in a supercomputer, don't use supercomputer drives in a consumer desktop ...) Always keep good backups. Backups ought to be part of your durability strategy. Otherwise you should be fine. Also try to have disks in RAID of the same size.

Danila Ladner
  • 5,331
  • 22
  • 31