Re: HBA or RAID-0 + BBU

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Den ons 19 apr. 2023 kl 00:55 skrev Murilo Morais <murilo@xxxxxxxxxxxxxx>:
> Good evening everyone!
> Guys, about the P420 RAID controller, I have a question about the operation
> mode: What would be better: HBA or RAID-0 with BBU (active write cache)?

As already said, always give ceph (and zfs and btrfs..) the raw disks
to handle for itself, instead of doing hardware striping/raiding and
so on.

There are multiple reasons for this, including weird/bad firmware and
(for raid0) loss of redundancy and so on, but there are also corner
cases where you may need/want to move disks from one box to another.
If you use "raw" disks, then what is on the platters most often is 1:1
to what the computer sees, and hence if you move the drive over to
another box, it will not matter if it has a HBA or Raid card, what
brand of disk controller it is and so on. The new server will also see
1:1 of the data the former machine wrote and this is what you want.

If you have a raid0/jbod/raid1/raidX setup on a particular raid
controller card with a particular firmware version, you may not be
able to move your complete raid set over to a newer box. Perhaps the
raid card model is no longer available, perhaps the raid firmware
logic is new and different on how to stripe data or place sectors on
the raid members. Perhaps it detects disks in the wrong order or
something.

It is very possible that you have zero problems with raid setups, but
the extra complexities when moving raid sets from one generation of
computer/controller to another makes the risk of some kind of
portability issue non-zero. Old grumpy storage admins don't like
non-zero risks if we actually can avoid it.

-- 
May the most significant bit of your life be positive.
_______________________________________________
ceph-users mailing list -- ceph-users@xxxxxxx
To unsubscribe send an email to ceph-users-leave@xxxxxxx



[Index of Archives]     [Information on CEPH]     [Linux Filesystem Development]     [Ceph Development]     [Ceph Large]     [Ceph Dev]     [Linux USB Development]     [Video for Linux]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]     [xfs]


  Powered by Linux