From: Frank Steinmetzger <Warp_7@gmx.de>
To: gentoo-user@lists.gentoo.org
Subject: Re: [gentoo-user] New hard drive. Is this normal? It looks like a connect problem.
Date: Tue, 13 May 2025 00:34:36 +0200 [thread overview]
Message-ID: <aCJ3fNhQ7hPdpruQ@schatulle> (raw)
In-Reply-To: <3351537.aeNJFYEL58@rogueboard>
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Am Wed, May 07, 2025 at 09:18:16AM +0100 schrieb Michael:
> On Wednesday, 7 May 2025 00:30:34 British Summer Time Dale wrote:
> > […]
> > I ran a hdparm test. I wanted to see as accurately as I could what the
> > speed was. I got this.
> >
> >
> >
> > root@nas ~ # hdparm -tT /dev/sdb
> >
> > /dev/sdb:
> > Timing cached reads: 7106 MB in 2.00 seconds = 3554.48 MB/sec
>
> These are rather pedestrian ^^^^ but I do not have any drives as large as
> yours to compare. A 4G drive here shows this:
>
> ~ # hdparm -tT /dev/sda
>
> /dev/sda:
> Timing cached reads: 52818 MB in 1.99 seconds = 26531.72 MB/sec
> Timing buffered disk reads: 752 MB in 3.00 seconds = 250.45 MB/sec
>
> That's an order of magnitude higher cached reads.
So you have a faster machine, possibly DDR5. Dale’s NAS is an old build.
That’s why it’s called cached.
From the manpage of hdparm: This measurement [of -T] is essentially an
indication of the throughput of the processor, cache, and memory of the
system under test. This displays the speed of reading directly from the
Linux buffer cache without disk access.
-------------------^^^^^^^^^^^^^^^^^^^
The output of -t is the actual physical bandwidth. And for a big current
haddrive, 250 MB/s is a decent normal value.
For comparison, this is from a nice SATA SSD (Crucial BX100 512 GB) on a
passive MiniPC with Celeron N5100 and DDR4 RAM (Zotac ZBox Nano CI331):
root@schatulle ~ # hdparm -Tt /dev/sda
/dev/sda:
Timing cached reads: 10950 MB in 2.00 seconds = 5480.12 MB/sec
Timing buffered disk reads: 1602 MB in 3.00 seconds = 533.56 MB/sec
As you can see, the SSD is almost at the practical limit of SATA 3, which is
600 MB/s. Wikipedia: Third-generation SATA interfaces run with a native
transfer rate of 6.0 Gbit/s; taking 8b/10b encoding into account, the
maximum uncoded transfer rate is 4.8 Gbit/s (600 MB/s).
> > Timing buffered disk reads: 802 MB in 3.00 seconds = 267.03 MB/sec
> > root@nas ~ #
> >
> >
> > From what I've seen of other drives, that appears to be SATA 3 or the
> > faster speed. So, it is slow to respond but connects and works fine.
SATA2 runs at half of SATA3, at 300 MB/s. So even if your drive ran at
SATA2, you wouldn’t notice any impact in performance.
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next prev parent reply other threads:[~2025-05-12 22:35 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-05 21:15 [gentoo-user] New hard drive. Is this normal? It looks like a connect problem Dale
2025-05-06 12:12 ` Michael
2025-05-06 12:59 ` Dale
2025-05-06 14:31 ` Michael
2025-05-06 20:51 ` Dale
2025-05-06 23:08 ` Wol
2025-05-07 0:16 ` Dale
2025-05-06 23:30 ` Dale
2025-05-07 8:18 ` Michael
2025-05-07 15:13 ` Dale
2025-05-10 15:53 ` Dale
2025-05-10 18:52 ` Michael
2025-05-12 8:11 ` Dale
2025-05-12 11:14 ` Michael
2025-05-13 6:30 ` Dale
2025-05-12 22:34 ` Frank Steinmetzger [this message]
2025-05-13 6:05 ` Dale
2025-05-13 8:30 ` Michael
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