Re: WD Blue 510 SSD and strange write performance
Date: Thu, 14 Mar 2024 18:56:48 UTC
Hi, > On 14 Mar 2024, at 18:47, mike tancsa <mike@sentex.net> wrote: > > This might be more of a hardware question than anything, but I noticed the drive is fairly fast on initial writes, but dramatically slows down over time with a consistent write. > > At bootup time, I can blast out a file (UFS2 mount) > > # dd if=/dev/zero of=/mnt/tmp/junk.bin.`date "+%s"` bs=1m status=progress count=4000 > 3735027712 bytes (3735 MB, 3562 MiB) transferred 7.014s, 533 MB/s > # > > nice and fast. But subsequent writes really start to tank. > > # dd if=/dev/zero of=/mnt/tmp/junk.bin.`date "+%s"` bs=1m status=progress count=4000 > 4128243712 bytes (4128 MB, 3937 MiB) transferred 46.048s, 90 MB/s > > # dd if=/dev/zero of=/mnt/tmp/junk.bin.`date "+%s"` bs=1m status=progress count=4000 > 3992977408 bytes (3993 MB, 3808 MiB) transferred 31.016s, 129 MB/s > > If I wait for 2min, it seems to be back to normal > > # sleep 120 ; dd if=/dev/zero of=/mnt/tmp/junk.bin.`date "+%s"` bs=1m status=progress count=4000 > 4137680896 bytes (4138 MB, 3946 MiB) transferred 9.025s, 458 MB/s > > Is there something going on behind the scenes limiting the amount of sustained writes these drives can handle ? Is it just a limitation of the SSD ? Probably (I don’t know for sure) these drives have a RAM write cache and really suck at committing from there to NVM. > I didnt notice such issues on some consumer Samsungs. The problem initially showed up for me when I was doing a series of zfs send | zfs recv on the same pool (so a lot of reads and writes at the same time) and I would get a bunch of errors on the WD disks. Replacing them with Samsungs avoids the errors. > > > === START OF INFORMATION SECTION === > Device Model: WD Blue SA510 2.5 1000GB > Serial Number: 240406800001 > LU WWN Device Id: 5 001b44 8b334e00b > Firmware Version: 52046100 > User Capacity: 1,000,204,886,016 bytes [1.00 TB] > Sector Size: 512 bytes logical/physical > Rotation Rate: Solid State Device > Form Factor: 2.5 inches > TRIM Command: Available, deterministic > Device is: Not in smartctl database 7.3/5528 > ATA Version is: ACS-4, ACS-2 T13/2015-D revision 3 > SATA Version is: SATA 3.2, 6.0 Gb/s (current: 6.0 Gb/s) > Local Time is: Thu Mar 14 14:41:58 2024 EDT > SMART support is: Available - device has SMART capability. > SMART support is: Enabled > > # camcontrol iden ada1 > pass1: <WD Blue SA510 2.5 1000GB 52046100> ACS-4 ATA SATA 3.x device > pass1: 600.000MB/s transfers (SATA 3.x, UDMA6, PIO 512bytes) > > protocol ACS-4 ATA SATA 3.x > device model WD Blue SA510 2.5 1000GB > firmware revision 52046100 > serial number 240406800001 > WWN 5001b448b334e00b > additional product id > cylinders 16383 > heads 16 > sectors/track 63 > sector size logical 512, physical 512, offset 0 > LBA supported 268435455 sectors > LBA48 supported 1953525168 sectors > PIO supported PIO4 > DMA supported WDMA2 UDMA6 > media RPM non-rotating > Zoned-Device Commands no > > Feature Support Enabled Value Vendor > read ahead yes yes > write cache yes yes > flush cache yes yes > Native Command Queuing (NCQ) yes 32 tags > NCQ Priority Information no > NCQ Non-Data Command no > NCQ Streaming no > Receive & Send FPDMA Queued no > NCQ Autosense no > SMART yes yes > security yes no > power management yes yes > microcode download yes yes > advanced power management yes no 0/0x00 > automatic acoustic management no no > media status notification no no > power-up in Standby no no > write-read-verify no no > unload no no > general purpose logging yes yes > free-fall no no > sense data reporting no no > extended power conditions no no > device statistics notification no no > Data Set Management (DSM/TRIM) yes > DSM - max 512byte blocks yes 8 > DSM - deterministic read yes any value > Trusted Computing no > encrypts all user data no > Sanitize yes block, > Sanitize - commands allowed yes > Sanitize - antifreeze lock yes > Host Protected Area (HPA) no > Accessible Max Address Config yes no 1953525168/1953525168 > > > RELENG_14 from today > > -- Bob Bishop rb@gid.co.uk