[stgt] [BUG] Tgt-1.0.8 exited unexpectedly
Hirokazu Takahashi
taka at valinux.co.jp
Mon Sep 27 05:41:40 CEST 2010
Hi,
> > I want VastSky which is a cluster storage system to use TGT as its
>
> Interesting. There are some similar experiments. IBM does the similar
> and I also did the similar with OpenStack. RedHat Hail does the
> similar with their own iSCSI target implementation.
>
> Out of curiosity, can VastSky avoid reading the old data?
>
> For example, WRITE goes to the three replica nodes, then WRITE to the
> same sector fails on the first replica node (e.g. timeout because the
> node is too busy) but succeeds with the rest two nodes (so the two
> nodes have the newer data).
>
> Then if the two nodes having the new data are down, is it possible
> that an initiator gets the old data from the first node (when the
> initiator issues READ to the same sector)?
In that case, VastSky just returns an EIO error. I won't change this
policy since volumes VastSky serves are supposed to be used with
file-systems on them. If a volume returns the wrong date including
the old data will cause a filesystem corruption easily.
VastSky updates all the mirrors synchronously. And only after all
the I/O requests are completed, it tells the owner that the request
is done.
Thank you,
Hirokazu Takahashi.
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