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For a company which primarily sells consumer products it makes sense to omit hardware checksums: You just detect errors which the end user might never notice, a
by zeotroph 7y ago
For a company which primarily sells consumer products it makes sense to omit hardware checksums: You just detect errors which the end user might never notice, a bit flip in a picture you never look at again might not be that bad.
For anyone who has ever heard of checksums this makes APFS a no-go of course.
- privateSFacct 7y agoI guess NTFS is also a "no go" for file storage then as well. What about ext4? Oh wait - no file data checksums - so a "no go". Actually, it turns out plenty of folks have built plenty of storage on these platforms - including APFS. In particular, for APFS, apple uses ECC for all hardware, uses fletcher checksums for metadata and I believe does a copy on write approach to help handle sudden power loss events etc. It seems to be working out OK for them given the prices they charge.
- isomorphic 7y agoYour point that other filesystems get by without checksums stands, but Apple does not use ECC for all hardware. Also, we are left to wonder if their "reliable" SSDs are as reliable as checksums at the filesystem layer (or as reliable as both). I suspect the answer is yes, for the majority of applications running atop APFS (which is to say, iOS). Probably not for video assets on that Promise MPX bay (i.e. "external" non-Apple storage media).
- AlphaSite 7y agoI do t think zfs can handle memory correction without ecc either, so is no better in this case.
- zeotroph 7y agoAll the next gen, copy on write filesystems have checksums: NTFS+ (ReFS) has it, ext4+ (btrfs) has it, but HPFS++ (APFS) has not. Bummer. At least optional checksums should be supported, then watchOS does not waste time with it but a user with 10k+ mac workstation who might still uses spinning rust for bulk data storage is SOL.
- floatboth 7y ago> NTFS+ (ReFS), ext4+ (btrfs) That's.. an extremely confusing way to put it. ReFS and btrfs are from-scratch new FSes.
- privateSFacct 7y agois ext4+ really shipping in volume? I checked RHEL, not the default. Is NTFS+ the default on Windows 10 / Windows Server 2016 or 2019? APFS is shipping today in quantity / as default and I believe they back migrated literally millions of devices to it something like a year ago. I don't understand the user use case with a 10K workstation and no raid (ie, with parity etc) + SSD with internal error correction. So this is a $10K workstation with magnetic disks and no other error correcting option / layer? Why do this?
- zeotroph 7y agoSLES (Suse) is going all in with btrfs, it is no ZFS but better than the equivalent RH solution of offering an LVM or other blocklevel layer of checksums. Not to mention all the ..BSD or ZfsOnLinux based storage solutions. I am not denying that APFS is a good FS, but not even having the option of checksums given its contemporaries was clearly a political and financial decision to benefit Apple and not its users. Pointing to an opaque mix of raid (and indeed, raid10 is not even enough), super-reliable SSDs and the full stack control doesn't make the lack of checksums any better.
- jplayer01 7y agoI don't really understand what the deal is with ReFS. Is this ever intended to reach normal consumers or are they happy with NTFS?
- rhinoceraptor 7y agoJust because you can't currently see any problems doesn't mean you're not surrounded by them. You can't see the problems because no one has turned on the lights.
- sneak 7y agoI use removable storage. SD cards, USB flash drives, USB hard disks. Apple’s hardware choices are irrelevant.
- throw0101a 7y agoThose other file systems were designed a while ago. If you're going to design one now, is there any reason to not have a checksuming capability? At least as an option, even though it may be default-off.