[9fans] Regenerating Venti Index Sections?

[9fans] Regenerating Venti Index Sections?

[Venkatesh Srinivas]

Hi,

I have a ~5GB Venti which had run for some time with one 256MB Index
Section; recently, the Index Section became corrupted. The Arenas are
intact. I was using plan9port's Venti.

Is it possible for me to reconstruct the index section? If so, how? Will
the Venti be able to run without it? If I can reconstruct it, can the
new index section be larger?

Thanks,
--vs

Re: [9fans] Regenerating Venti Index Sections?

[Adrian Tritschler]

Venkatesh Srinivas wrote:
> Hi,
>
> I have a ~5GB Venti which had run for some time with one 256MB Index
> Section; recently, the Index Section became corrupted. The Arenas are
> intact. I was using plan9port's Venti.

I run a similar system, a ubuntu linux box with Venti under p9p with a
VMware guest system that is a plan9 cpu server.

> Is it possible for me to reconstruct the index section?

Yes

 > If so, how?

By reading the manuals :-) "man 8 venti-fmt"

Rebuild index with "venti/buildindex venti.conf"


 > Will the Venti be able to run without it?

 > If I can reconstruct it, can the
> new index section be larger?

Yes.  Prior to rebuilding your index, create new isect file(s) or
partitions, add them to your venti.conf, format them with, for example:

venti/fmtisect isectXYZ isectXYZ

then rebuild the index.

> Thanks,
> --vs
	Adrian

Re: [9fans] Regenerating Venti Index Sections?

[a]

// Is it possible for me to reconstruct the index section?

Yes. See venti-fmt(8). If you want to stop here, you can
try checkindex first, and if that doesn't work for you, go
to buildindex.

// Will the Venti be able to run without it?

No, you need an index. The bloom filter is the only
optional (but recommended) component.

// ...can the new index section be larger?

Yes. You can either replace your old index (required if
you've suffered a hardware failure, for example) or
build a new index using your old index as a part. (if
you've just run out of space). In either case, you'll
need to format each index section (fmtisect) and then
the index itself (fmtindex) before regerating the index
for your currend data log (buildindex).

anthony