BrttClne22 Posted May 16, 2018 Share Posted May 16, 2018 Hoping one of you smart souls can shed some light on an issue I've found today. I've done a lot of Googling, but no dice. I had been experiencing some iowait lockups when radarr/sonarr moved a file from an unassigned disk to my 'media' share with the cache setting to 'Yes'. I confirmed that turning the cache setting to 'Off', mitigated the iowait issues but I would prefer it be written to the cache first. Using a write speed test script posted by @johnnie.black, I ran two separate tests against my cache drive. When formatted as BTRFS (sorry, I don't have the exact results for these): /mnt/cache/test.dat 450 MBps /mnt/user/media/test.dat 60 MBps I ditched BTRFS, thinking that may be the problem. I didn't really have a use case for it anyways as I only have a single cache drive atm. Here are the same tests with XFS writing 10240000000 bytes to: /mnt/cache/test.dat 3681144+0 records in 3681144+0 records out 3769491456 bytes (3.8 GB, 3.5 GiB) copied, 5.00031 s, 754 MB/s 6741953+0 records in 6741953+0 records out 6903759872 bytes (6.9 GB, 6.4 GiB) copied, 10.0016 s, 690 MB/s 9420809+0 records in 9420809+0 records out 9646908416 bytes (9.6 GB, 9.0 GiB) copied, 15.0049 s, 643 MB/s 10000000+0 records in 10000000+0 records out 10240000000 bytes (10 GB, 9.5 GiB) copied, 16.1416 s, 634 MB/s write complete, syncing removed '/mnt/cache/test.dat' writing 10240000000 bytes to: /mnt/user/media/test.dat 327258+0 records in 327258+0 records out 335112192 bytes (335 MB, 320 MiB) copied, 5.00024 s, 67.0 MB/s 664063+0 records in 664063+0 records out 680000512 bytes (680 MB, 648 MiB) copied, 10.0015 s, 68.0 MB/s 993568+0 records in 993568+0 records out 1017413632 bytes (1.0 GB, 970 MiB) copied, 15.0029 s, 67.8 MB/s 1321207+0 records in 1321207+0 records out 1352915968 bytes (1.4 GB, 1.3 GiB) copied, 20.0045 s, 67.6 MB/s 1652369+0 records in 1652369+0 records out 1692025856 bytes (1.7 GB, 1.6 GiB) copied, 25.0059 s, 67.7 MB/s 1988734+0 records in 1988734+0 records out 2036463616 bytes (2.0 GB, 1.9 GiB) copied, 30.0073 s, 67.9 MB/s 2316253+0 records in 2316253+0 records out 2371843072 bytes (2.4 GB, 2.2 GiB) copied, 35.0089 s, 67.7 MB/s 2649459+0 records in 2649459+0 records out 2713046016 bytes (2.7 GB, 2.5 GiB) copied, 40.0102 s, 67.8 MB/s 2984946+0 records in 2984946+0 records out 3056584704 bytes (3.1 GB, 2.8 GiB) copied, 45.0115 s, 67.9 MB/s 3321507+0 records in 3321507+0 records out 3401223168 bytes (3.4 GB, 3.2 GiB) copied, 50.0129 s, 68.0 MB/s 3651156+0 records in 3651156+0 records out 3738783744 bytes (3.7 GB, 3.5 GiB) copied, 55.0142 s, 68.0 MB/s 3980471+0 records in 3980471+0 records out 4076002304 bytes (4.1 GB, 3.8 GiB) copied, 60.0157 s, 67.9 MB/s 4314105+0 records in 4314105+0 records out 4417643520 bytes (4.4 GB, 4.1 GiB) copied, 65.0171 s, 67.9 MB/s 4647805+0 records in 4647805+0 records out 4759352320 bytes (4.8 GB, 4.4 GiB) copied, 70.0184 s, 68.0 MB/s 4981473+0 records in 4981473+0 records out 5101028352 bytes (5.1 GB, 4.8 GiB) copied, 75.02 s, 68.0 MB/s 5315667+0 records in 5315667+0 records out 5443243008 bytes (5.4 GB, 5.1 GiB) copied, 80.0215 s, 68.0 MB/s 5645479+0 records in 5645479+0 records out 5780970496 bytes (5.8 GB, 5.4 GiB) copied, 85.0229 s, 68.0 MB/s 5974952+0 records in 5974952+0 records out 6118350848 bytes (6.1 GB, 5.7 GiB) copied, 90.0242 s, 68.0 MB/s 6310587+0 records in 6310587+0 records out 6462041088 bytes (6.5 GB, 6.0 GiB) copied, 95.0256 s, 68.0 MB/s 6638667+0 records in 6638667+0 records out 6797995008 bytes (6.8 GB, 6.3 GiB) copied, 100.027 s, 68.0 MB/s 6965658+0 records in 6965658+0 records out 7132833792 bytes (7.1 GB, 6.6 GiB) copied, 105.029 s, 67.9 MB/s 7297553+0 records in 7297553+0 records out 7472694272 bytes (7.5 GB, 7.0 GiB) copied, 110.03 s, 67.9 MB/s 7625676+0 records in 7625676+0 records out 7808692224 bytes (7.8 GB, 7.3 GiB) copied, 115.033 s, 67.9 MB/s 7953216+0 records in 7953216+0 records out 8144093184 bytes (8.1 GB, 7.6 GiB) copied, 120.035 s, 67.8 MB/s 8282188+0 records in 8282188+0 records out 8480960512 bytes (8.5 GB, 7.9 GiB) copied, 125.037 s, 67.8 MB/s 8613901+0 records in 8613901+0 records out 8820634624 bytes (8.8 GB, 8.2 GiB) copied, 130.04 s, 67.8 MB/s Just to prove that it is in fact set to use the cache drive (I also double checked the file system of /mnt/cache/media as it was writing): Diagnostics attached. Thanks for your help! zeus-diagnostics-20180515-2039.zip Quote Link to comment
John_M Posted May 16, 2018 Share Posted May 16, 2018 Your experience reminds me of this thread. In practice I see no actual problem. Maybe the test is somehow not valid. 1 Quote Link to comment
BrttClne22 Posted May 16, 2018 Author Share Posted May 16, 2018 Thanks for pointing that out, very interesting thread. After reading it, I did a write test of a 25 GB file from my Windows 10 VM (running on a separate NVME drive) to the media share (Samsung Pro SSD) and speeds were VERY similar to the /mnt/cache test. That puts my mind a little more at ease. Quote Link to comment
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