Carlos E. R. composed on 2019-02-28 14:06 (UTC+0100):
I suspect that in your case, trimming is disabled.
It turns out I had set discard as a filesystem option when formatting all EXT4 filesystems on the PNY SSD. So, continuous trim was on, as well as the fstrim.timer engaged, since 30 January. As yet I've found nothing about the ramifications of trying to use both at the same time. To recap, the 120G PNY SSD gave: when new: # hdparm -t /dev/sda: Timing buffered disk reads: 770 MB in 3.00 seconds = 256.62 MB/sec of late: # hdparm -t /dev/sda /dev/sda: Timing buffered disk reads: 22 MB in 3.10 seconds = 7.09 MB/sec I've replaced the PNY with this XPG 128G SSD: https://www.newegg.com/Product/Product.aspx?reviews=all&Item=N82E16820215167 I forgot to save hdparm -t output of the XPG before putting it into boot service. I do remember running it at the time with both 42.3 and TW and getting 528.## with both. Now that it's been in use 3 days, it's already down: hdparm -t /dev/sda /dev/sda: Timing buffered disk reads: 1524 MB in 3.00 seconds = 507.78 MB/sec But, only just 2 hours ago I turned off discard as a mount option, and haven't yet rebooted. The fstrim timer isn't due until tonight, so I guess I'll be rebooting some time before then. I emailed PNY about the 97% throughput loss according to its own RMA instructions provided by multiple locations over 72 hours ago, and filled out its technical support web form for same at the same time; no response to either as yet. :-( -- Evolution as taught in public schools is religion, not science. Team OS/2 ** Reg. Linux User #211409 ** a11y rocks! Felix Miata *** http://fm.no-ip.com/ -- To unsubscribe, e-mail: opensuse-support+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-support+owner@opensuse.org