Significant improvements coming in Linux 3.5 | Hacker News Reader

Significant improvements coming in Linux 3.5

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71 pointsTsiolkovsky14 comments

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> The Ext4 filesystem can now add checksums to its metadata to help recognise data tampering.

That is really interesting. (And not just data tampering but possibly data corruption.)

> many systems produced by Apple have had this kind of "FireWire target disk mode" for a while now.

Since 2000.

It looks like this will include support for USB disks, though, which Apple doesn't yet support in TDM.

.. but unlike Linux, the Apple Firewire Target mode can't be used while Mac OSX is running on the machine. In Apples' case, its implemented in EFI - whereas with Linux, it will be possible to use the 'target mode' while the machine is still running.

One complication in that scenario is that you can't mount a (normal) filesystem while exposing it over SCSI target (because then it would be mounted twice).

Actually you can't mount anything from the target drive, because the whole drive is exposed over the network as a SCSI device.

The point is I can now very easily build a Linux-based RAID stack that works with my Macs over Firewire:

Kernel-Firewire-Target:0:1->/home/disks/image00.dd & image01.dd &image02.dd &etc.

Build a big Linux box with much SSD and other slower disks, wire up a light Mac farm to it with Firewire, point each node to a relevant loop file on some path, and managed storage networks are a cinch.

That would have been awesome years ago; now I'd just use gigabit iSCSI. Thunderbolt target mode OTOH...

for some broad definition of "significant"

If you don't have graphics support for your current card or need the new profiling it's significant. The "target mode" is cool but it's not a significant use case.

I expected something bigger as well. From the release mail of Linus:

  It's a pretty normal release - roughly 60% drivers, 20% arch updates,
  and 20% "all over" - filesystems, documentation, tools, you name it.

  Nothing hugely special springs to mind - there's some memory
  compaction issue that is still being discussed, but I don't think
  there's anything particularly scary or special that stands out over
  everything else in the -rc1.

Well... The Systemtap userspace probes seem nice, as does the ext4 metadata checksumming, CODEL queue management and the connection repair (albeit I have only played with the idea of moving a live VM from one box to another).

Yes. They are significant. Not as significant as the delta between Solaris 10 and 11 or Windows 7 and 8, but, considering the time elapsed since the previous significant improvements, I'd think it's quite impressive.

Incremental improvement is good.

Being able to act as a FC target could be pretty powerful as well. I wish I could do that now on my linux boxes...could create a nice little storage network.

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