Re: [gpfsug-discuss] gpfs client and turning off swap
On 08/11/2019 16:52, Skylar Thompson wrote: > We don't run diskless systems, but use cgroups where possible to limit the > damage users can do to a node. We derate the node's total usable memory by > 2GB (OS) + GPFS pagepool to avoid paging whenever possible. > I would add that as the RAM in the node rises swap becomes pointless. We find that it's a bit pointless at 192GB of RAM in a node, for our large memory nodes which have 3TB of RAM, swap is utterly pointless. In fact there is more RAM than there is disk space. In either case the old rules about setting swap to be twice RAM or even swap equals RAM are either hard to achieve to impossible. JAB. -- Jonathan A. Buzzard Tel: +44141-5483420 HPC System Administrator, ARCHIE-WeSt. University of Strathclyde, John Anderson Building, Glasgow. G4 0NG ___ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org http://gpfsug.org/mailman/listinfo/gpfsug-discuss
Re: [gpfsug-discuss] gpfs client and turning off swap
On Fri, 08 Nov 2019 10:25:24 -0600, Damir Krstic said: > I was wondering if it's safe to turn off swap on gpfs client machines? we > have a case where checkpointing is swapping and we would like to prevent it > from doing so by disabling swap. However, the gpfs manual admin. GPFS will work just fine without a swap space if the system has sufficient RAM. However, if checkpointing is swapping, you don't have enough RAM (at least with your current configuration), and turning off swap will result in processes being killed due to lack of memory. You *might* get it to work by tuning system config variables to reduce RAM consumption. But that's better tested while you still have swap defined, and not removing swap until you have a system not needing it. pgpbhXeAQ9yXD.pgp Description: PGP signature ___ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org http://gpfsug.org/mailman/listinfo/gpfsug-discuss
Re: [gpfsug-discuss] gpfs client and turning off swap
We don't run diskless systems, but use cgroups where possible to limit the damage users can do to a node. We derate the node's total usable memory by 2GB (OS) + GPFS pagepool to avoid paging whenever possible. On Fri, Nov 08, 2019 at 11:31:20AM -0500, david_john...@brown.edu wrote: > We have most of our clients network booted and diskless ??? no swap possible. > Gpfs still works until someone runs the node out of memory > > -- ddj > Dave Johnson > > > On Nov 8, 2019, at 11:25 AM, Damir Krstic wrote: > > > > ??? > > I was wondering if it's safe to turn off swap on gpfs client machines? we > > have a case where checkpointing is swapping and we would like to prevent it > > from doing so by disabling swap. However, the gpfs manual admin. manual > > states to have swap enabled and sufficiently large, but it does not > > distinguish between clients and IO servers. > > > > Let me know when you get a chance. -- -- Skylar Thompson (skyl...@u.washington.edu) -- Genome Sciences Department, System Administrator -- Foege Building S046, (206)-685-7354 -- University of Washington School of Medicine ___ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org http://gpfsug.org/mailman/listinfo/gpfsug-discuss
Re: [gpfsug-discuss] gpfs client and turning off swap
Thanks - that's what I thought. We also (many refreshes ago) ran diskless images with RedHat 6 and GPFS 3.4 and ran into no issues with having swap off. I figured to ask in case something has changed with the Spectrum Scale. Damir On Fri, Nov 8, 2019 at 10:31 AM wrote: > We have most of our clients network booted and diskless — no swap > possible. Gpfs still works until someone runs the node out of memory > > -- ddj > Dave Johnson > > > On Nov 8, 2019, at 11:25 AM, Damir Krstic > wrote: > > > > > > I was wondering if it's safe to turn off swap on gpfs client machines? > we have a case where checkpointing is swapping and we would like to prevent > it from doing so by disabling swap. However, the gpfs manual admin. manual > states to have swap enabled and sufficiently large, but it does not > distinguish between clients and IO servers. > > > > Let me know when you get a chance. > > > > Thank you. > > Damir > > ___ > > gpfsug-discuss mailing list > > gpfsug-discuss at spectrumscale.org > > http://gpfsug.org/mailman/listinfo/gpfsug-discuss > ___ > gpfsug-discuss mailing list > gpfsug-discuss at spectrumscale.org > http://gpfsug.org/mailman/listinfo/gpfsug-discuss > ___ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org http://gpfsug.org/mailman/listinfo/gpfsug-discuss
Re: [gpfsug-discuss] gpfs client and turning off swap
We have most of our clients network booted and diskless — no swap possible. Gpfs still works until someone runs the node out of memory -- ddj Dave Johnson > On Nov 8, 2019, at 11:25 AM, Damir Krstic wrote: > > > I was wondering if it's safe to turn off swap on gpfs client machines? we > have a case where checkpointing is swapping and we would like to prevent it > from doing so by disabling swap. However, the gpfs manual admin. manual > states to have swap enabled and sufficiently large, but it does not > distinguish between clients and IO servers. > > Let me know when you get a chance. > > Thank you. > Damir > ___ > gpfsug-discuss mailing list > gpfsug-discuss at spectrumscale.org > http://gpfsug.org/mailman/listinfo/gpfsug-discuss ___ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org http://gpfsug.org/mailman/listinfo/gpfsug-discuss
[gpfsug-discuss] gpfs client and turning off swap
I was wondering if it's safe to turn off swap on gpfs client machines? we have a case where checkpointing is swapping and we would like to prevent it from doing so by disabling swap. However, the gpfs manual admin. manual states to have swap enabled and sufficiently large, but it does not distinguish between clients and IO servers. Let me know when you get a chance. Thank you. Damir ___ gpfsug-discuss mailing list gpfsug-discuss at spectrumscale.org http://gpfsug.org/mailman/listinfo/gpfsug-discuss
