Hi Matteo,
Ceph introduces latency into the write path and so what you are seeing is typical. If you increase the iodepth of the fio test you should get higher results though, until you start maxing out your CPU. Nick From: ceph-users [mailto:ceph-users-boun...@lists.ceph.com] On Behalf Of Matteo Dacrema Sent: 26 October 2015 11:20 To: ceph-us...@ceph.com Subject: [ceph-users] BAD nvme SSD performance Hi all, I've recently buy two Samsung SM951 256GB nvme PCIe SSDs and built a 2 OSD ceph cluster with min_size = 1. I've tested them with fio ad I obtained two very different results with these two situations with fio. This is the command : fio --ioengine=libaio --direct=1 --name=test --filename=test --bs=4k --size=100M --readwrite=randwrite --numjobs=200 --group_reporting On the OSD host I've obtained this result: bw=575493KB/s, iops=143873 On the client host with a mounted volume I've obtained this result: Fio executed on the client osd with a mounted volume: bw=9288.1KB/s, iops=2322 I've obtained this results with Journal and data on the same disk and also with Journal on separate SSD. I've two OSD host with 64GB of RAM and 2x Intel Xeon E5-2620 @ 2.00GHz and one MON host with 128GB of RAM and 2x Intel Xeon E5-2620 @ 2.00 GHz. I'm using 10G mellanox NIC and Switch with jumbo frames. I also did other test with this configuration ( see attached Excel workbook ) Hardware configuration for each of the two OSD nodes: 3x 100GB Intel SSD DC S3700 with 3 * 30 GB partition for every SSD 9x 1TB Seagate HDD Results: about 12k IOPS with 4k bs and same fio test. I can't understand where is the problem with nvme SSDs. Anyone can help me? Here the ceph.conf: [global] fsid = 3392a053-7b48-49d3-8fc9-50f245513cc7 mon_initial_members = mon1 mon_host = 192.168.1.3 auth_cluster_required = cephx auth_service_required = cephx auth_client_required = cephx osd_pool_default_size = 2 mon_client_hung_interval = 1.0 mon_client_ping_interval = 5.0 public_network = 192.168.1.0/24 cluster_network = 192.168.1.0/24 mon_osd_full_ratio = .90 mon_osd_nearfull_ratio = .85 [mon] mon_warn_on_legacy_crush_tunables = false [mon.1] host = mon1 mon_addr = 192.168.1.3:6789 [osd] osd_journal_size = 30000 journal_dio = true journal_aio = true osd_op_threads = 24 osd_op_thread_timeout = 60 osd_disk_threads = 8 osd_recovery_threads = 2 osd_recovery_max_active = 1 osd_max_backfills = 2 osd_mkfs_type = xfs osd_mkfs_options_xfs = "-f -i size=2048" osd_mount_options_xfs = "rw,noatime,inode64,logbsize=256k,delaylog" filestore_xattr_use_omap = false filestore_max_inline_xattr_size = 512 filestore_max_sync_interval = 10 filestore_merge_threshold = 40 filestore_split_multiple = 8 filestore_flusher = false filestore_queue_max_ops = 2000 filestore_queue_max_bytes = 536870912 filestore_queue_committing_max_ops = 500 filestore_queue_committing_max_bytes = 268435456 filestore_op_threads = 2 Best regards, Matteo
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