If you need larger than 1MB objects and you are only serving these objects
to 5 users at a time.  It really sounds like memcache is the wrong tool for
your project.  You might want to look into something like MongoDB which has
a larger object limit of 4MB.  There are a number of key value stores that
can handle even larger size objects.

Could you explain a little more on what type of binary data you
are manipulating ?

On Mon, Sep 20, 2010 at 8:25 PM, MikeG. <[email protected]> wrote:

> Hi,
>
> I'm starting a project in which I would like to have the entire DB in
> cache.
> The reason is that my transactions are reading large amount of data
> from the DB to generate
> a deliverable blob.
>
> I have no concurrency issues. I will always have around 5 users max
> concurrently and most
> of the time it will be single user. SO I look at the context as
> virtually single user.
>
> To avoid this massive DB reading (of large count of large chunks) I
> would like to have it
> permanently in memory.
> When any modification of a record happened it is not being written to
> the DB until the
> big blob final product is delivered and the local system goes idle.
> Only then modifications are written to the DB. Upon successful
> completion of DB update the local system sends a
> message to the recipient of the product to inform it that the DB is
> now in sync with the product
> at hand and it can be consumed.
>
> Now, to hold 1TB in memory I need a cluster and not a small one. I
> have decided to use
> memory mapped files such that my RAM is virtual memory. Easy to get
> large file system of
> several TBs.
>
> My question - is there any limit memcached has as far as cache size?
>
> Also, memcached (the C implementation) has a 1MB record size limit. 1)
> What's the reason
> for that? 2) Can it be changed (with a hacked private version) 3) Does
> Jmemcached has the
> same limit?
>
> Thanks,
> -Michael
>

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