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RomanSt
Asked: 2013-04-09 16:03:34 +0800 CST

Are hardware RAID systems with silent corruption protection available?

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I know ZFS has protection against silent corruption, but I'm building a Windows server. Are there options out there for adding local, silent-corruption-protected storage to a Windows server, or is ZFS-over-network the only option?

I would like to pay extra for something that can compute the checksums fast enough to make the hard drive the bottleneck. Are such I/O cards available?

storage

2 Answers

  1. Currently only ZFS (and soon BTRFS) have chechsumming of all I/O operations. NTFS does checksumming on journal writes, as do many linux filesystems.

    The higher end RAID cards also do block level validations in the background. It isn't filesystem aware but it is sufficient to suss out bad clusters and relocate data proactively. The point of ZFS systems is to avoid such hardware based checksumming systems, but RAID cards have been doing this validation for many years now.

    The hardware solutions we have now provide silent corruption protection from the storage controller down to the actual media. ZFS extends that protection to the filesystem layer in the kernel and when used in isolation of modern hardware solutions can protect the whole stack. If you want that kind of protection for Windows, you won't get it; you'll have to rely on hardware solutions and take your chances with the storage-card to application transmission path.

    Using a ZFS filer doesn't get you any additional protection vs NTFS+hardware either. You still have the NIC to application route unprotected in the Windows server, which is the same vulnerability as the storage-card to the app in the hardware solution. The only reason a ZFS-filer would be beneficial would be if you don't have the right hardware and are relying on ZFS to do all the heavy lifting.

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  2. Yes, as Mark Wagner pointed out in the comments, T10-PI can be used for that. I think majority if not all LSI (Broadcom) controllers support it, at least those I used. You have to either buy a disks formatted in one of T10-PI modes. Or format disks yourself with sg_format (though it might be dangerous if the process is interrupted). I think majority of modern disks are T10-PI capable, it's easy to check it in the specs of the particular disk. Although note, that once upon a time I measured performance and it was reduced by around 10% with T10-PI array in some tests.

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