IDS i/o and Solaris
Neil Truby asked whether it was sensible to run IDS 10.0FC8W2 on Solaris 10 using cooked files on a directio-mounted filesystem, since the customer's sysadmin had good results doing this with Oracle. Frank Langelage warned that directio is a whole-filesystem mount option (fine only if the filesystem is dedicated to Informix) and recommended raw devices for best performance. Fernando Nunes noted IDS 10 does not use KAIO on cooked files, and that DIO/CIO at best approaches raw performance, so there is little to gain if raw is already available. Another poster simply advised pushing back on the sysadmin. No definitive decision or test result is recorded.
Auto-generated by DrWatson from the posts below — may be imperfect; read the full thread.
IDS 10.0FC8W2 on Solaris 10. We're just migrating to a new server from IDS 10.0FC8W2 on Solaris 9. The customer's SysAdmin has seen great results on Oracle using Solaris 10 Direct i/o onto file system containers (ie cooked files), and really wants to try same on the Informix database. Any reason not to give it a try?
Neil Truby wrote: > IDS 10.0FC8W2 on Solaris 10. > > We're just migrating to a new server from IDS 10.0FC8W2 on Solaris 9. > > The customer's SysAdmin has seen great results on Oracle using Solaris > 10 Direct i/o onto file system containers (ie cooked files), and really > wants to try same on the Informix database. > > Any reason not to give it a try? Not having dedicated filesystems for the informix datafiles would be a reason against that. Direct IO is a mount option for the whole filesystem, so all I/O to files on this filesystem bypass the buffer chache of the OS. No problem for the informix data as there is the cache of IDS, but other file IO will suffer. But why not use raw devices? From our experience this will give the best performance.
"Frank Langelage" <frank@lafr.de> wrote in message news:6nec2lFlcrnuU1@mid.individual.net... > Neil Truby wrote: >> IDS 10.0FC8W2 on Solaris 10. >> >> We're just migrating to a new server from IDS 10.0FC8W2 on Solaris 9. >> >> The customer's SysAdmin has seen great results on Oracle using Solaris 10 >> Direct i/o onto file system containers (ie cooked files), and really >> wants to try same on the Informix database. >> >> Any reason not to give it a try? > > Not having dedicated filesystems for the informix datafiles would be a > reason against that. > Direct IO is a mount option for the whole filesystem, so all I/O to files > on this filesystem bypass the buffer chache of the OS. > No problem for the informix data as there is the cache of IDS, but other > file IO will suffer. > But why not use raw devices? > From our experience this will give the best performance. The whole fs would be dedicated to /opt/informix, which would be chunks plus binaries only.
Neil Truby wrote: > IDS 10.0FC8W2 on Solaris 10. > > We're just migrating to a new server from IDS 10.0FC8W2 on Solaris 9. > > The customer's SysAdmin has seen great results on Oracle using Solaris > 10 Direct i/o onto file system containers (ie cooked files), and really > wants to try same on the Informix database. > > Any reason not to give it a try? IDS 10, running on cooked files will not use KAIO. I cannot quantify the impact off this... From everything I read, what we can achieve from DIO _and_ CIO is to get real close to RAW. If you're using RAW, you should answer this question first: What will you benefit? Regards, -- Fernando Nunes Portugal http://informix-technology.blogspot.com My email works... but I don't check it frequently...
"Fernando Nunes" <domusonline@gmail.com> wrote in message news:get93l$5fm$1@registered.motzarella.org... > Neil Truby wrote: >> IDS 10.0FC8W2 on Solaris 10. >> >> We're just migrating to a new server from IDS 10.0FC8W2 on Solaris 9. >> >> The customer's SysAdmin has seen great results on Oracle using Solaris 10 >> Direct i/o onto file system containers (ie cooked files), and really >> wants to try same on the Informix database. >> >> Any reason not to give it a try? > > IDS 10, running on cooked files will not use KAIO. > I cannot quantify the impact off this... > > From everything I read, what we can achieve from DIO _and_ CIO is to get > real close to RAW. If you're using RAW, you should answer this question > first: What will you benefit? The customer's SysAdmin wants to use direct_io because he understands it, and it works well with Oracle. If the difference is marginal I'd rather not antagonise him by arguing about it and appearing like a bigoted zealot. Even though I am ;-)
Neil Truby wrote: > "Fernando Nunes" <domusonline@gmail.com> wrote in message > news:get93l$5fm$1@registered.motzarella.org... >> Neil Truby wrote: >>> IDS 10.0FC8W2 on Solaris 10. >>> >>> We're just migrating to a new server from IDS 10.0FC8W2 on Solaris 9. >>> >>> The customer's SysAdmin has seen great results on Oracle using Solaris 10 >>> Direct i/o onto file system containers (ie cooked files), and really >>> wants to try same on the Informix database. >>> >>> Any reason not to give it a try? >> IDS 10, running on cooked files will not use KAIO. >> I cannot quantify the impact off this... >> >> From everything I read, what we can achieve from DIO _and_ CIO is to get >> real close to RAW. If you're using RAW, you should answer this question >> first: What will you benefit? > > The customer's SysAdmin wants to use direct_io because he understands it, > and it works well with Oracle. > If the difference is marginal I'd rather not antagonise him by arguing about > it and appearing like a bigoted zealot. Even though I am ;-) In all seriousness, I'd antagonise him. This box isn't running Oracle and he needs to wake up. -- Cheers, Obnoxio The Clown http://obotheclown.blogspot.com