I was not able to find those parameters on my client nodes, OSS or MGS nodes. Here is how I was extracting all parameters .
mkdir -p lctl_list_param_R/ cd lctl_list_param_R/ lctl list_param -R * > lctl_list_param_R [opc@lustre-client-1 lctl_list_param_R]$ less lctl_list_param_R | grep ahead llite.lfsbv-ffff98231c3bc000.statahead_agl llite.lfsbv-ffff98231c3bc000.statahead_max llite.lfsbv-ffff98231c3bc000.statahead_running_max llite.lfsnvme-ffff98232c30e000.statahead_agl llite.lfsnvme-ffff98232c30e000.statahead_max llite.lfsnvme-ffff98232c30e000.statahead_running_max [opc@lustre-client-1 lctl_list_param_R]$ I also tried these commands: Not working: On client nodes lctl get_param llite.lfsbv-*.max_read_ahead_mb error: get_param: param_path 'llite/lfsbv-*/max_read_ahead_mb': No such file or directory [opc@lustre-client-1 lctl_list_param_R]$ Works On client nodes lctl get_param llite.*.statahead_agl llite.lfsbv-ffff98231c3bc000.statahead_agl=1 llite.lfsnvme-ffff98232c30e000.statahead_agl=1 [opc@lustre-client-1 lctl_list_param_R]$ From: "Moreno Diego (ID SIS)" <diego.mor...@id.ethz.ch> Date: Tuesday, December 10, 2019 at 2:06 AM To: Pinkesh Valdria <pinkesh.vald...@oracle.com>, "lustre-discuss@lists.lustre.org" <lustre-discuss@lists.lustre.org> Subject: Re: [lustre-discuss] Degraded read performance with Large Bulk IO (16MB RPC) With that kind of degradation performance on read I would immediately think on llite’s max_read_ahead parameters on the client. Specifically these 2: max_read_ahead_mb: total amount of MB allocated for read ahead, usually quite low for bandwidth benchmarking purposes and when there’re several files per client max_read_ahead_per_file_mb: the default is quite low for 16MB RPCs (only a few RPCs per file) You probably need to check the effect increasing both of them. Regards, Diego From: lustre-discuss <lustre-discuss-boun...@lists.lustre.org> on behalf of Pinkesh Valdria <pinkesh.vald...@oracle.com> Date: Tuesday, 10 December 2019 at 09:40 To: "lustre-discuss@lists.lustre.org" <lustre-discuss@lists.lustre.org> Subject: [lustre-discuss] Degraded read performance with Large Bulk IO (16MB RPC) I was expecting better or same read performance with Large Bulk IO (16MB RPC), but I see degradation in performance. Do I need to tune any other parameter to benefit from Large Bulk IO? Appreciate if I can get any pointers to troubleshoot further. Throughput before - Read: 2563 MB/s - Write: 2585 MB/s Throughput after - Read: 1527 MB/s. (down by ~1025) - Write: 2859 MB/s Changes I did are: On oss - lctl set_param obdfilter.lfsbv-*.brw_size=16 On clients - unmounted and remounted - lctl set_param osc.lfsbv-OST*.max_pages_per_rpc=4096 (got auto-updated after re-mount) - lctl set_param osc.*.max_rpcs_in_flight=64 (Had to manually increase this to 64, since after re-mount, it was auto-set to 8, but read/write performance was poor) - lctl set_param osc.*.max_dirty_mb=2040. (setting the value to 2048 was failing with : Numerical result out of range error. Previously it was set to 2000 when I got good performance. My other settings: - lnetctl net add --net tcp1 --if $interface –peer-timeout 180 –peer-credits 128 –credits 1024 - echo "options ksocklnd nscheds=10 sock_timeout=100 credits=2560 peer_credits=63 enable_irq_affinity=0" > /etc/modprobe.d/ksocklnd.conf - lfs setstripe -c 1 -S 1M /mnt/mdt_bv/test1
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