Deutsch   English   Français   Italiano  
<wwvsevmvv1s.fsf@LkoBDZeT.terraraq.uk>

View for Bookmarking (what is this?)
Look up another Usenet article

Path: ...!weretis.net!feeder9.news.weretis.net!feeder8.news.weretis.net!news.nntp4.net!nntp.terraraq.uk!.POSTED.tunnel.sfere.anjou.terraraq.org.uk!not-for-mail
From: Richard Kettlewell <invalid@invalid.invalid>
Newsgroups: comp.sys.raspberry-pi
Subject: Re: Move bookworm system from SSD to NVME
Date: Sat, 03 Aug 2024 10:02:07 +0100
Organization: terraraq NNTP server
Message-ID: <wwvsevmvv1s.fsf@LkoBDZeT.terraraq.uk>
References: <v8cqd6$1gdnp$1@dont-email.me> <v8e73l$1o2dm$1@dont-email.me>
	<v8frll$24ic1$1@dont-email.me> <v8ft4f$250uj$1@dont-email.me>
	<v8gamm$28554$1@dont-email.me>
	<20240801171000.46ce321a2dd0cb03be7cba00@eircom.net>
	<v8ghss$290sp$1@dont-email.me>
	<20240801192923.a827ba8d22853e9bc6c5cfb3@eircom.net>
	<v8gm3e$2atj2$1@dont-email.me> <v8go75$2bmb1$1@dont-email.me>
	<v8i9jp$2oohc$1@dont-email.me> <v8ikp3$2qqdd$2@dont-email.me>
	<v8ip08$2ralv$1@dont-email.me> <v8iph9$2rqib$2@dont-email.me>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: 8bit
Injection-Info: innmantic.terraraq.uk; posting-host="tunnel.sfere.anjou.terraraq.org.uk:172.17.207.6";
	logging-data="124468"; mail-complaints-to="usenet@innmantic.terraraq.uk"
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux)
Cancel-Lock: sha1:KYT0vMZFHagmpU/gfPKU9BTQSfQ=
X-Face: h[Hh-7npe<<b4/eW[]sat,I3O`t8A`(ej.H!F4\8|;ih)`7{@:A~/j1}gTt4e7-n*F?.Rl^
     F<\{jehn7.KrO{!7=:(@J~]<.[{>v9!1<qZY,{EJxg6?Er4Y7Ng2\Ft>Z&W?r\c.!4DXH5PWpga"ha
     +r0NzP?vnz:e/knOY)PI-
X-Boydie: NO
Bytes: 2544
Lines: 24

The Natural Philosopher <tnp@invalid.invalid> writes:
> On 02/08/2024 15:03, Björn Lundin wrote:
>> dd'ing 500 Gb to an ssd disk, I've seen sync taking 30 s or more
>> and sync is of course started AFTER dd is done
>> So - how do you know it is done its internal business?
>> Not all drives have blinking LEDs
>> sync makes it easy to know
> 
> Even sync may not be enough.
> SSDS/NVM have their own internal  caching.

The sync syscall (and command) will flush those too.

Unless you’ve paid extra for a drive with a huge cache I would expect
the extra delay while the on-drive cache is flushed to be absolutely
tiny in human terms, and certainly tiny compared to flushing the OS’s
cache, which can be multiple gigabytes.

References:
* https://www.kernel.org/doc/Documentation/block/writeback_cache_control.txt
* https://linux.die.net/man/2/sync
* https://github.com/torvalds/linux/blob/master/fs/sync.c#L87

-- 
https://www.greenend.org.uk/rjk/