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Why does this cheap SSD benchmark so slow

General Discussion by glasgow_tom 20 replies 2K views
glasgow_tom

Member OP

3 #1

Bought this "NVMe" KVM from RackNerd for my old CS:S community box. dd shows 45 MB/s seq write. That's slower than my 2007 WD Caviar. Kids play Valorant now but source engine servers need tickrate stability and this thing stutters every time the disk gets hit. Feels like playing on 15 tick with packet loss. Their ad said "blazing fast NVMe storage" but this is clearly some QEMU emulated nonsense or a saturated controller. Anyone else get bait-and-switched like this? Community's dead anyway but I wanted to host one last 24/7 for the old crew.

kenji3

Member

#2

45 MB/s strongly suggests a QEMU virtio-blk device backed by a spinning rust ZFS pool with no ARC cache. I have seen this on several Asia-Pacific budget providers. You can check with `lsblk -d -o NAME,ROTA,TYPE,MODEL` and `cat /sys/block/vda/queue/rotational`. If it returns 0 despite the performance, that is emulation. Proper NVMe should show 1+ GB/s on any YABS run — https://github.com/masonr/yet-another-bench-script. I would request a refund with evidence.

conbini > datacenter snacks
everseoul

Member

1 #3

Gg wp RackNerd thats rough buddy my minecraft box on CloudCone gets 2gb/s and my valheim lag is zero this is just lag for everything not even game lag just existence lag gonna cite this thread for my refund too section whatever about false advertising

LE

Member

#4
kenji3 said:
If it returns 0 despite the performance, that is emulation.

Or it's a SATA SSD on a crowded node. My BuyVM slice in LU does the same dance, shows as nvme0n1 but it's really a Samsung PM883 behind a LSI card. 80 MB/s during their "maintenance windows" which is all the time lately — https://status.buyvm.net

kenji3

Member

#5
leshspace said:
Or it's a SATA SSD on a crowded node.

SATA SSD should still do 400+ MB/s sequential. 45 MB/s is pool contention or rust, nothing else. I have measured PM883 on my home lab, steady 530 MB/s.

conbini > datacenter snacks
glasgow_tom

Member OP

3 #6
kenji3 said:
SATA SSD should still do 400+ MB/s sequential.

Aye, ran the commands. ROTA=0, TYPE=disk, MODEL="QEMU HARDDISK". So it's lying about being rotational too. Ticket sent, not holding my breath.

FyreJun

Member

#7

QEMU HARDDISK with virtio-blk and no iothread pinned. You can check `ps aux | grep iothread` and `cat /proc/interrupts | grep virtio`. If the virtio queues all hit CPU0, that's your stutter right there. I had this on a RamNode instance years back, same symptoms.

pieter_rtm

Member

#8

This is why I just rent dedicated from Hetzner now. Their AX42 is €34.60, NVMe is real Samsung PM9A3, and I get 3.5 GB/s every time. No more guessing if my "neighbors" are running chia plots.

Containers before it was cool
everseoul

Member

#9
pieter_rtm said:
Hetzner now. Their AX42 is €34.60

34 euro is like 50k won my whole budget is 5 dollars american lmao. CloudCone was 2.80 on BF sale. You europeans and your expensive taste.

RO

Member

#10

I have RackNerd in Chicago, same plan. Mine does 180 MB/s write which is bad but not 45 bad. Maybe glasgow_tom got unlucky with the node, or they're oversold worse on UK routes.

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