Can you also send me your patch? We have been waiting for the storage engine, but we are not close to maxing out our systems yet.
Thanks' David On 7/13/10, Mitch <gmi...@gmail.com> wrote: > Hi Marten! > > I have developed a patch for memcached 1.4.x that splits memcached's > slab store into metadata and data bits, so that the key/values can > live on flash without a tremendous performance penalty. Ultimately, I > predict the best solution will be to use the storage engine branch and/ > or Northscale's membase, but for the time being the patch works pretty > well. I'll send you a private email with more info. > > thanks! > Mitch (from Fusion-io) > > On Jul 9, 10:01 am, Marten Lehmann <coolcoyo...@googlemail.com> wrote: >> Hello, >> >> I know that memcached is designed to get its speed from the fast >> access to RAM. But RAM is still very expensive - even with the amount >> of RAM you get for the same money increasing every year. >> >> When I thought of using PCIe SSDs instead of RAM I wasn't doing this >> with regard to persistence of objects. I just noticed, that the Fusion- >> io's ioDrives are working with near-RAM speed, having the PCIe bus as >> the only bottleneck in speed (don't mix it up with SATA SSDs). An >> ioDrive 160 GB with SLC memory is available for less than $6,000 and >> is capable to perform more than 100,000 random IOPS (read and write), >> whereas with ECC RAM you'd have to pay a multiple of that amount the >> get the same ressources. >> >> I don't know of any way to use a block device (like the ioDrive) as >> RAM, you can only use RAM as a block device (which doesn't help in >> this situation). So for the emerging market of PCIe SSDs (many high >> performance databases are using this as replacement for RAID 10 arrays >> and large RAM) it would be necessary to extend or branch memcached to >> support SSD block devices. >> >> Did someone start with that, is this possibly already on the roadmap, >> or did the maintainers refuse to extend memcache with this option for >> a reason? >> >> Btw.: We are using memcached in conjunction with nginx as a web proxy >> to our backend webservers to cache images and other static files, >> which improves performance a lot. But 64 GB of RAM is much more >> expensiv than 160 GB of an ioDrive PCIe SSD. >> >> Kind regards >> Marten
