Bristol Digest, Vol 614, Issue 1

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Today's Topics:

1. Take your time! How to slow down rsync or tar ? (old
computer) (Winnie Lacesso)
2. Re: Take your time! How to slow down rsync or tar ? (old
computer) (Alex Butcher)
3. Re: Take your time! How to slow down rsync or tar ? (old
computer) (Colin M. Strickland)
4. Re: Take your time! How to slow down rsync or tar ? (old
computer) (David Smith)
5. Re: Take your time! How to slow down rsync or tar ? (old
computer) (Ashley Pittman)
6. Re: Take your time! How to slow down rsync or tar ? (old
computer) (Zak Wilcox)
7. Re: Take your time! How to slow down rsync or tar ? (old
computer) (Shane McEwan)
8. Re: Take your time! How to slow down rsync or tar ? (old
computer) (Marc Gray)


----------------------------------------------------------------------

Message: 1
Date: Mon, 17 Aug 2015 15:18:38 +0100 (BST)
From: Winnie Lacesso <Winnie.Lacesso@bristol.ac.uk>
To: bristol@mailman.lug.org.uk
Subject: [bristol] Take your time! How to slow down rsync or tar ?
(old computer)
Message-ID:
<alpine.LRH.2.02.1508171515200.32576@rescue.phy.bris.ac.uk>
Content-Type: TEXT/PLAIN; charset=US-ASCII


On an old computer I want to be very gentle with (hopefully to keep it
alive as long as possible) I always use nice -n 19 rsync blah blah or when
tar'ing something large up, & generally do nothing else on it while that
happens.

Even with nice -n 19 the CPU load rises, the fan goes mad, etc etc.
Poor old thing.

Is there any way to instruct the operation to GO REAL SLOW? It's perfectly
OK if these operations take an hour vs 10min! or even several hours, like
overnight.

One thought is instead of
nice -n 19 rsync <options> $dirname /target/location
to do it in a loop like
for d in $dirname/*; do
nice -n 19 rsync <options> $d /target/location/$dirname/.
sleep <whatever number of seconds>
done

But even that's not ideal, most of the subdirs are large & that still
causes ++CPU load & fan-go-mad wheezing.

Any ideas? I can't see any rsync, tar, or other nice options that might
do what's wanted.

Grateful for Advice!




------------------------------

Message: 2
Date: Mon, 17 Aug 2015 15:27:34 +0100 (BST)
From: Alex Butcher <lug@assursys.co.uk>
To: Winnie.lacesso@bristol.ac.uk, Bristol and Bath Linux User Group
<bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Take your time! How to slow down rsync or tar ?
(old computer)
Message-ID:
<alpine.LRH.2.11.1508171521120.26213@zlgugi.of5.nffheflf.cev>
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed

On Mon, 17 Aug 2015, Winnie Lacesso wrote:

> On an old computer I want to be very gentle with (hopefully to keep it
> alive as long as possible) I always use nice -n 19 rsync blah blah or when
> tar'ing something large up, & generally do nothing else on it while that
> happens.

ionice might help as well.

But probably the only thing that would help for certain would be to create a
wrapper library for glibc that added sleep() calls to commonly called
functions.

Or, clean or replace those fans and it should be fine running at full pelt.
And if not, it probably ought to be retired sooner rather than later.

> Is there any way to instruct the operation to GO REAL SLOW? It's perfectly
> OK if these operations take an hour vs 10min! or even several hours, like
> overnight.

Wouldn't it increase the chances that the created backups are internally
inconsistent?

Best Regards,
Alex



------------------------------

Message: 3
Date: Mon, 17 Aug 2015 15:28:29 +0100
From: "Colin M. Strickland" <cms@beatworm.co.uk>
To: "Winnie Lacesso" <Winnie.lacesso@bristol.ac.uk>, "Bristol and Bath
Linux User Group" <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Take your time! How to slow down rsync or tar ?
(old computer)
Message-ID: <5248263F-A102-44F2-AD8E-A76AEBA9A949@beatworm.co.uk>
Content-Type: text/plain; format=flowed

On 17 Aug 2015, at 15:18, Winnie Lacesso wrote:

> On an old computer I want to be very gentle with (hopefully to keep it
> alive as long as possible) I always use nice -n 19 rsync blah blah or
> when
> tar'ing something large up, & generally do nothing else on it while
> that
> happens.
>
> Even with nice -n 19 the CPU load rises, the fan goes mad, etc etc.
> Poor old thing.
>
> Is there any way to instruct the operation to GO REAL SLOW? It's
> perfectly
> OK if these operations take an hour vs 10min! or even several hours,
> like
> overnight.
>

Hi Winnie,

re-niceing will lower the scheduling priority, but maybe you're still
saturating your I/O ?

Have a look at the 'pv' command, which is a tool you can insert into a
pipeline to display statistics about data throughput, and more
pertinently also allows you to impose rate limits so it can act as a
throttle.

--
Regards,
Colin M. Strickland, cms, 'that guy'.



------------------------------

Message: 4
Date: Mon, 17 Aug 2015 14:29:31 +0000
From: David Smith <David.Smith@imgtec.com>
To: "Winnie.lacesso@bristol.ac.uk" <Winnie.lacesso@bristol.ac.uk>,
"Bristol and Bath Linux User Group" <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Take your time! How to slow down rsync or tar ?
(old computer)
Message-ID:
<15A9D35B5490FC49AC0524AE3A085F089CD3F5@BRMAIL01.br.imgtec.org>
Content-Type: text/plain; charset="us-ascii"

> -----Original Message-----
> From: Bristol [mailto:bristol-bounces@mailman.lug.org.uk] On Behalf Of
> Winnie Lacesso
> On an old computer I want to be very gentle with (hopefully to keep it alive
> as long as possible) I always use nice -n 19 rsync blah blah or when tar'ing
> something large up, & generally do nothing else on it while that happens.


Two suggestions:
1. Have a second process that repeatedly sends SIGTSTP (equivalent of Ctrl-Z) to the process then resumes it.
2. Download the source of rsync/tar/etc and create your own.




------------------------------

Message: 5
Date: Mon, 17 Aug 2015 15:44:32 +0100
From: Ashley Pittman <ashley@pittman.co.uk>
To: bristol@mailman.lug.org.uk
Subject: Re: [bristol] Take your time! How to slow down rsync or tar ?
(old computer)
Message-ID: <55D1F350.6020202@pittman.co.uk>
Content-Type: text/plain; charset=windows-1252; format=flowed

On 17/08/15 15:29, David Smith wrote:
>> -----Original Message-----
>> From: Bristol [mailto:bristol-bounces@mailman.lug.org.uk] On Behalf Of
>> Winnie Lacesso
>> On an old computer I want to be very gentle with (hopefully to keep it alive
>> as long as possible) I always use nice -n 19 rsync blah blah or when tar'ing
>> something large up, & generally do nothing else on it while that happens.
>
> Two suggestions:
> 1. Have a second process that repeatedly sends SIGTSTP (equivalent of Ctrl-Z) to the process then resumes it.
> 2. Download the source of rsync/tar/etc and create your own.

Or try using the bwlimit option of rsync, hopefully it'll do the right
thing and sleep in the kernel rather than blocking on the CPU.

Ashley,



------------------------------

Message: 6
Date: Mon, 17 Aug 2015 15:58:44 +0100
From: Zak Wilcox <iwilcox@iwilcox.me.uk>
To: bristol@mailman.lug.org.uk
Subject: Re: [bristol] Take your time! How to slow down rsync or tar ?
(old computer)
Message-ID: <55D1F6A4.6010005@iwilcox.me.uk>
Content-Type: text/plain; charset=windows-1252

On 17/08/15 15:27, Alex Butcher wrote:
> Or, clean or replace those fans and it should be fine running at
> full pelt.

Yeah, I'd be looking at that first too.

> But probably the only thing that would help for certain would be to
> create a wrapper library for glibc that added sleep() calls to
> commonly called functions.

Maybe layering the 'delay' device-mapper target over the top of the
original block device would achieve the same? Never actually tried it,
mind.



------------------------------

Message: 7
Date: Mon, 17 Aug 2015 16:01:31 +0100
From: Shane McEwan <shane@mcewan.id.au>
To: bristol@mailman.lug.org.uk
Subject: Re: [bristol] Take your time! How to slow down rsync or tar ?
(old computer)
Message-ID: <55D1F74B.2090308@mcewan.id.au>
Content-Type: text/plain; charset=utf-8

G'day!

The 'nice' command only changes the priority of the process. If nothing
else is happening on the machine then a niced process will take as much
CPU as it can. Only when the machine is doing other things will the
niced process get less CPU time.

With 'rsync' you could try the '--bwlimit=RATE' option to throttle the
bandwidth. Usually it's used to limit the amount of network bandwidth
it's using but I suspect if you give it a small enough number it will
also slow it down when using it to copy files on the same machine.
Unfortunately 'tar' doesn't have such an option.

You could also try using 'cpulimit'
(http://www.cyberciti.biz/faq/cpu-usage-limiter-for-linux/) which works
by pausing and unpausing a process in order to slow it down.

Shane.

On 17/08/15 15:18, Winnie Lacesso wrote:
>
> On an old computer I want to be very gentle with (hopefully to keep it
> alive as long as possible) I always use nice -n 19 rsync blah blah or when
> tar'ing something large up, & generally do nothing else on it while that
> happens.
>
> Even with nice -n 19 the CPU load rises, the fan goes mad, etc etc.
> Poor old thing.
>
> Is there any way to instruct the operation to GO REAL SLOW? It's perfectly
> OK if these operations take an hour vs 10min! or even several hours, like
> overnight.
>
> One thought is instead of
> nice -n 19 rsync <options> $dirname /target/location
> to do it in a loop like
> for d in $dirname/*; do
> nice -n 19 rsync <options> $d /target/location/$dirname/.
> sleep <whatever number of seconds>
> done
>
> But even that's not ideal, most of the subdirs are large & that still
> causes ++CPU load & fan-go-mad wheezing.
>
> Any ideas? I can't see any rsync, tar, or other nice options that might
> do what's wanted.
>
> Grateful for Advice!
>
>
> _______________________________________________
> Bristol mailing list
> Bristol@mailman.lug.org.uk
> https://mailman.lug.org.uk/mailman/listinfo/bristol
>



------------------------------

Message: 8
Date: Mon, 17 Aug 2015 18:47:13 +0100
From: Marc Gray <marc.gray@gmail.com>
To: Bristol and Bath Linux User Group <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Take your time! How to slow down rsync or tar ?
(old computer)
Message-ID:
<CAPorv7VNxA2tUX28KD4WdcVue9CYPNd2jeY-HRTWydYR4USuhg@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

>
>
> On 17/08/15 15:18, Winnie Lacesso wrote:
> >
> > On an old computer I want to be very gentle with (hopefully to keep it
> > alive as long as possible) I always use nice -n 19 rsync blah blah or
> when
> > tar'ing something large up, & generally do nothing else on it while that
> > happens.
> >
> > Even with nice -n 19 the CPU load rises, the fan goes mad, etc etc.
> > Poor old thing.
> >
> > Is there any way to instruct the operation to GO REAL SLOW? It's
> perfectly
> > OK if these operations take an hour vs 10min! or even several hours, like
> > overnight.
>
>
Lower the CPU clock speed:
http://www.thinkwiki.org/wiki/How_to_use_cpufrequtils

Use --bwlimit on rsync.?
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