I need more ram, but I can't.

classic Classic list List threaded Threaded
143 messages Options
1234 ... 8
Reply | Threaded
Open this post in threaded view
|

I need more ram, but I can't.

Carlos E. R.-2
-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA1



Hi,

I need more ram than my 8GiB, but my board doesn't allow it. I use swap,
but Leap is very slow when swapping; I have the feeling that it is
slower than other releases.

So I wonder if there is some type of small hard disk that can be used
for fast swap. SSD? Would it wear out? SSD is typically slow at writing.

A RAM based "disk"? No need for battery backup, unless to keep the
format. Does it exist?

- --
Cheers

  Carlos E. R.
  (from 42.2 x86_64 "Malachite" at Telcontar)


-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2

iEYEARECAAYFAlm/yMsACgkQtTMYHG2NR9WoeQCgkKbSLo1AZhJa29JhdYjE3myF
HdsAn3dHyHmeqVDqNz08xUPhj712RDVz
=S0mM
-----END PGP SIGNATURE-----

--
To unsubscribe, e-mail: [hidden email]
To contact the owner, e-mail: [hidden email]

Reply | Threaded
Open this post in threaded view
|

Re: I need more ram, but I can't.

Patrick Shanahan-2
* Carlos E. R. <[hidden email]> [09-18-17 09:24]:
> Hi,
>
> I need more ram than my 8GiB, but my board doesn't allow it. I use swap,
> but Leap is very slow when swapping; I have the feeling that it is
> slower than other releases.
>
> So I wonder if there is some type of small hard disk that can be used for
> fast swap. SSD? Would it wear out? SSD is typically slow at writing.

ssd would be much faster for swap than revolving rust.
 
> A RAM based "disk"? No need for battery backup, unless to keep the format.
> Does it exist?

if you are short on ram, how would you justify allocating ram for swap?
yes you can do that.

but...

my intel based mb specifys 24gig ram but I have 32 and from two different
specs.  this boundary spec is not always updated when motherboards/bioses
receive changes.  you could *try* more ram

I cannot speak for amd.
--
(paka)Patrick Shanahan       Plainfield, Indiana, USA          @ptilopteri
http://en.opensuse.org    openSUSE Community Member    facebook/ptilopteri
Registered Linux User #207535                    @ http://linuxcounter.net
Photos: http://wahoo.no-ip.org/piwigo                    paka @ IRCnet freenode

--
To unsubscribe, e-mail: [hidden email]
To contact the owner, e-mail: [hidden email]

Reply | Threaded
Open this post in threaded view
|

Re: I need more ram, but I can't.

Carlos E. R.-2
On 2017-09-18 15:39, Patrick Shanahan wrote:

> * Carlos E. R. <[hidden email]> [09-18-17 09:24]:
>> Hi,
>>
>> I need more ram than my 8GiB, but my board doesn't allow it. I use swap,
>> but Leap is very slow when swapping; I have the feeling that it is
>> slower than other releases.
>>
>> So I wonder if there is some type of small hard disk that can be used for
>> fast swap. SSD? Would it wear out? SSD is typically slow at writing.
>
> ssd would be much faster for swap than revolving rust.
But often not for write, and has a limited number of ops.

I have a machine with an SSD for main disk and feels slow.

>
>> A RAM based "disk"? No need for battery backup, unless to keep the format.
>> Does it exist?
>
> if you are short on ram, how would you justify allocating ram for swap?
> yes you can do that.

No. On a card, forming a disk. New hardware.


> but...
>
> my intel based mb specifys 24gig ram but I have 32 and from two different
> specs.  this boundary spec is not always updated when motherboards/bioses
> receive changes.  you could *try* more ram

No, I remember the specs, max is 8.

--
Cheers / Saludos,

                Carlos E. R.
                (from 42.2 x86_64 "Malachite" at Telcontar)


signature.asc (188 bytes) Download Attachment
Reply | Threaded
Open this post in threaded view
|

Re: I need more ram, but I can't.

Patrick Shanahan-2
* Carlos E. R. <[hidden email]> [09-18-17 09:49]:

> On 2017-09-18 15:39, Patrick Shanahan wrote:
> > * Carlos E. R. <[hidden email]> [09-18-17 09:24]:
> >> Hi,
> >>
> >> I need more ram than my 8GiB, but my board doesn't allow it. I use swap,
> >> but Leap is very slow when swapping; I have the feeling that it is
> >> slower than other releases.
> >>
> >> So I wonder if there is some type of small hard disk that can be used for
> >> fast swap. SSD? Would it wear out? SSD is typically slow at writing.
> >
> > ssd would be much faster for swap than revolving rust.
>
> But often not for write, and has a limited number of ops.
>
> I have a machine with an SSD for main disk and feels slow.
>
> >
> >> A RAM based "disk"? No need for battery backup, unless to keep the format.
> >> Does it exist?
> >
> > if you are short on ram, how would you justify allocating ram for swap?
> > yes you can do that.
>
> No. On a card, forming a disk. New hardware.
>
>
> > but...
> >
> > my intel based mb specifys 24gig ram but I have 32 and from two different
> > specs.  this boundary spec is not always updated when motherboards/bioses
> > receive changes.  you could *try* more ram
>
> No, I remember the specs, max is 8.

you misunderstand.  the "specs" are not always correct for your mb,
usually the max which matches all, not necessarily the max for you mb.
try more, it will complain or fault if not usable.  try more ram.  



--
(paka)Patrick Shanahan       Plainfield, Indiana, USA          @ptilopteri
http://en.opensuse.org    openSUSE Community Member    facebook/ptilopteri
Registered Linux User #207535                    @ http://linuxcounter.net
Photos: http://wahoo.no-ip.org/piwigo                    paka @ IRCnet freenode

--
To unsubscribe, e-mail: [hidden email]
To contact the owner, e-mail: [hidden email]

Reply | Threaded
Open this post in threaded view
|

Re: I need more ram, but I can't.

Lew Wolfgang
In reply to this post by Carlos E. R.-2
On 09/18/2017 06:23 AM, Carlos E. R. wrote:

> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
>
>
> Hi,
>
> I need more ram than my 8GiB, but my board doesn't allow it. I use swap, but Leap
> is very slow when swapping; I have the feeling that it is slower than other releases.
>
> So I wonder if there is some type of small hard disk that can be used for fast
> swap. SSD? Would it wear out? SSD is typically slow at writing.

We've been using SSD's for root and swap partitions on scientific workstations
and servers since 2008 or so, and we've never had a problem. Indeed, the first
one I installed is still working after running 24/7 for nine years. Writing to SSD's
may be slower than reading, but the writing is still MUCH faster than writing
to spinning disks.  I'd give it a try, Carlos.  Your motherboard does support SATA,
right?

BTW, I installed my latest server a few weeks ago that has 512-GB of ECC RAM,
and my users have still managed to fill it up and overflow to swap. Yes, SSD
drives for root and swap too.  Leap 42.3 really screams on it!

Regards,
Lew






--
To unsubscribe, e-mail: [hidden email]
To contact the owner, e-mail: [hidden email]

Reply | Threaded
Open this post in threaded view
|

Re: I need more ram, but I can't.

Knurpht - Gertjan Lettink
In reply to this post by Patrick Shanahan-2
Op maandag 18 september 2017 15:56:59 CEST schreef Patrick Shanahan:
> > No, I remember the specs, max is 8.

So was my old server/workstation. A BIOS update and now the max is 16 GB.
--
Gertjan Lettink, a.k.a. Knurpht

openSUSE Board Member
openSUSE Forums Team

--
To unsubscribe, e-mail: [hidden email]
To contact the owner, e-mail: [hidden email]

Reply | Threaded
Open this post in threaded view
|

Re: I need more ram, but I can't.

Anthony Youngman
In reply to this post by Lew Wolfgang
On 18/09/17 15:33, Lew Wolfgang wrote:

>> So I wonder if there is some type of small hard disk that can be used
>> for fast swap. SSD? Would it wear out? SSD is typically slow at writing.
>
> We've been using SSD's for root and swap partitions on scientific
> workstations
> and servers since 2008 or so, and we've never had a problem. Indeed, the
> first
> one I installed is still working after running 24/7 for nine years.
> Writing to SSD's
> may be slower than reading, but the writing is still MUCH faster than
> writing
> to spinning disks.  I'd give it a try, Carlos.  Your motherboard does
> support SATA,
> right?

It's been mentioned before - the "test to destruction" test on SSDs. I
think it took about 18 months of a machine locked into a "write, read,
rewrite, erase, reformat, restart" loop before the drives even started
thinking of failing.

If your PC only has 8GB of ram, are you really going to thrash the drive
that hard?

The other thing is, depending on the PC, might it be simpler to just
upgrade the mobo? I guess you're on DDR2? My DDR3 mobo is 16GB. And I'm
looking at upgrading - the new setup will take 4 x 8 or 16 GB sticks,
and the cost will be about £150 plus ram (£50 for the mobo, £100 for the
processor, ram maybe £30 a stick?) My current machine is probably a good
five years old, if not more ...

Cheers,
Wol

--
To unsubscribe, e-mail: [hidden email]
To contact the owner, e-mail: [hidden email]

Reply | Threaded
Open this post in threaded view
|

Re: I need more ram, but I can't.

Per Jessen
Wols Lists wrote:

> On 18/09/17 15:33, Lew Wolfgang wrote:
>>> So I wonder if there is some type of small hard disk that can be
>>> used for fast swap. SSD? Would it wear out? SSD is typically slow at
>>> writing.
>>
>> We've been using SSD's for root and swap partitions on scientific
>> workstations
>> and servers since 2008 or so, and we've never had a problem. Indeed,
>> the first
>> one I installed is still working after running 24/7 for nine years.
>> Writing to SSD's
>> may be slower than reading, but the writing is still MUCH faster than
>> writing
>> to spinning disks.  I'd give it a try, Carlos.  Your motherboard does
>> support SATA,
>> right?
>
> It's been mentioned before - the "test to destruction" test on SSDs. I
> think it took about 18 months of a machine locked into a "write, read,
> rewrite, erase, reformat, restart" loop before the drives even started
> thinking of failing.

c't magazine recently ran an article on their results of long-term
testing SSDs.

> The other thing is, depending on the PC, might it be simpler to just
> upgrade the mobo? I guess you're on DDR2? My DDR3 mobo is 16GB. And
> I'm looking at upgrading - the new setup will take 4 x 8 or 16 GB
> sticks, and the cost will be about £150 plus ram (£50 for the mobo,
> £100 for the processor, ram maybe £30 a stick?) My current machine is
> probably a good five years old, if not more ...

Mine is ancient, an MSI board with an AMD Phenom IIRC.  Dating back to
openSUSE 10.3. Only 4Gb RAM.  That's pretty much the standard for our
office machines.




--
Per Jessen, Zürich (14.3°C)
http://www.dns24.ch/ - free dynamic DNS, made in Switzerland.


--
To unsubscribe, e-mail: [hidden email]
To contact the owner, e-mail: [hidden email]

Reply | Threaded
Open this post in threaded view
|

Re: I need more ram, but I can't.

gregfreemyer
In reply to this post by Patrick Shanahan-2
On Mon, Sep 18, 2017 at 9:56 AM, Patrick Shanahan <[hidden email]> wrote:

> * Carlos E. R. <[hidden email]> [09-18-17 09:49]:
>> On 2017-09-18 15:39, Patrick Shanahan wrote:
>> > * Carlos E. R. <[hidden email]> [09-18-17 09:24]:
>> >> Hi,
>> >>
>> >> I need more ram than my 8GiB, but my board doesn't allow it. I use swap,
>> >> but Leap is very slow when swapping; I have the feeling that it is
>> >> slower than other releases.
>> >>
>> >> So I wonder if there is some type of small hard disk that can be used for
>> >> fast swap. SSD? Would it wear out? SSD is typically slow at writing.
>> >
>> > ssd would be much faster for swap than revolving rust.
>>
>> But often not for write, and has a limited number of ops.
>>
>> I have a machine with an SSD for main disk and feels slow.

Is this a desktop?  If so, for ~$20 you can buy a NVMe SSD controller
card.  It fits into a PCIe slot.  (Assuming you have an empty slot).

NVMe SSDs scream.  Mine benchmarks above 1.5 GB/sec.  (That's B for
Bytes, not b for bits).  I have openSUSE 42.2 running on it.  But I
have plenty of RAM, so I don't think the PC ever swaps.

Not as fast as RAM, but 10x the speed of rotating drives even if you
ignore seek times.

I have 2 of the NVMe SSDs.  One was way expensive (2 TB).

But the Samsung PM951 128GB is under $100.

Greg

--
To unsubscribe, e-mail: [hidden email]
To contact the owner, e-mail: [hidden email]

Reply | Threaded
Open this post in threaded view
|

Re: I need more ram, but I can't.

John Andersen-2
In reply to this post by Carlos E. R.-2
On 09/18/2017 06:23 AM, Carlos E. R. wrote:

>
>
> Hi,
>
> I need more ram than my 8GiB, but my board doesn't allow it. I use swap, but Leap is very slow when
> swapping; I have the feeling that it is slower than other releases.
>
> So I wonder if there is some type of small hard disk that can be used for fast swap. SSD? Would it
> wear out? SSD is typically slow at writing.
>
> A RAM based "disk"? No need for battery backup, unless to keep the format. Does it exist?
>
> -- Cheers
>
>     Carlos E. R.
>     (from 42.2 x86_64 "Malachite" at Telcontar)

Another few points to consider Carlos:

Sometimes you think you are using swap, but you check and find out that the machine is set up
by default to resist swapping until it gets desperate for memory.  This has been the trend lately
but it is a silly default when you have swap on an SSD.

I'm currently running 42.2 on a laptop limited to 4gig. I crank up the swappiness (60) and crank
down the cache pressure (50). I WANT it to swap.  I want it to swap early and often.

Its using 4 gig of memory with a 6gig swap on SSD in a dual core machine.
Sometimes running VMs I'm using more swap space than I am real memory. Its fast as hell.

In /etc/sysctl.conf
vm.swappiness = 60
vm.vfs_cache_pressure = 50

I make much more use of swap this way than with the default settings.

Now about your worry regarding write to SSD....  Yes write is slower than read.
But only because Read is so blindingly fast.
Writing on ssd is light years ahead of HDD write speeds.  You can only call it slow when viewed in
comparison to the same SSD's read speed.

So don't be afraid to write on your SSD, and don't be afraid to use the hell out of your SSD.  You
will send the machine to recycle long before your ssd wears out.

Another possible source of slowness:  discard option in fstab.
You want to remove that from every partition in fstab that sits on ssd.
Instead use systemd's fstrim.timer.

sudo systemctl enable fstrim.timer
sudo systemctl start fstrim.timer
sudo systemctl status fstrim.service

This will trim you drives once a week (which is plenty) rather than inserting trim
operations after ever file delete operation. Discard in the fstab entry can make the machine
"feel" slow and causes excess SSD access.

One recommendation for swap on ssd (or any partition on ssd) is to over provision, provide more
space than you actually need so as not to force trim operations for space recovery. Ned 8 gig?
then partition for 10.

Some links I've found on this subject:

http://www.linux-magazine.com/Issues/2016/187/SSD-tuning

Somewhat dated: Mostly from Ted Ts'o who knows a thing or two about file systems:
https://thunk.org/tytso/blog/2009/02/22/should-filesystems-be-optimized-for-ssds/
Newer post by Ted Ts'o on this:
https://forums.freebsd.org/threads/56951/#post-328912

Also Less specific:
https://arstechnica.com/gadgets/2015/04/ask-ars-my-ssd-does-garbage-collection-so-i-dont-need-trim-right/

ArchWiki also recommends against discard:
https://wiki.archlinux.org/index.php/Solid_State_Drives

Also, (side issue  nothing to do with swap) btrfs is not really optimized for ssd.
https://btrfs.wiki.kernel.org/index.php/FAQ#Is_Btrfs_optimized_for_SSD.3F








--
After all is said and done, more is said than done.


signature.asc (188 bytes) Download Attachment
Reply | Threaded
Open this post in threaded view
|

Re: I need more ram, but I can't.

John Andersen-2
In reply to this post by Anthony Youngman
On 09/18/2017 08:28 AM, Wols Lists wrote:
> It's been mentioned before - the "test to destruction" test on SSDs.
http://techreport.com/review/27909/the-ssd-endurance-experiment-theyre-all-dead

They all lasted orders of magnitude beyond their warranted/designed life time.

--
After all is said and done, more is said than done.

--
To unsubscribe, e-mail: [hidden email]
To contact the owner, e-mail: [hidden email]

Reply | Threaded
Open this post in threaded view
|

Re: I need more ram, but I can't.

Anton Aylward-2
In reply to this post by Carlos E. R.-2
There may be other solutions.

Tweaking the VM setting has been suggested, but there are a lot of variables and
it is going to be application dependent.  Allocation memory to file buffers,
inode caching, directory caching, big-page merging, and more are examples of
situations where the 'swapiness' and swap speed might be of secondary interest.

Putting the whole system on a PCIe/NVMe SSD will speed things up, yes, but it
may be hiding what could be achieved by application-specific tuning.
--
Rulers

The best rulers are scarcely known by their subjects;
The next best are loved and praised;
The next are feared;
The next despised:
They have no faith in their people,
And their people become unfaithful to them.
When the best rulers achieve their purpose
Their subjects claim the achievement as their own.
                -- Lao Tse, "Tao Te Ching"

--
To unsubscribe, e-mail: [hidden email]
To contact the owner, e-mail: [hidden email]

Reply | Threaded
Open this post in threaded view
|

Re: I need more ram, but I can't.

Carlos E. R.-2
In reply to this post by Knurpht - Gertjan Lettink
On 2017-09-18 17:06, Knurpht - Gertjan Lettink wrote:
> Op maandag 18 september 2017 15:56:59 CEST schreef Patrick Shanahan:
>>> No, I remember the specs, max is 8.
>
> So was my old server/workstation. A BIOS update and now the max is 16 GB.

Huh. The MB has some years and I don't remember updates available. If
there were updates for the amount of RAM, I'd noticed.

--
Cheers / Saludos,

                Carlos E. R.

  (from 42.2 x86_64 "Malachite" (Minas Tirith))


signature.asc (220 bytes) Download Attachment
Reply | Threaded
Open this post in threaded view
|

Re: I need more ram, but I can't.

Carlos E. R.-2
In reply to this post by Patrick Shanahan-2
On 2017-09-18 15:56, Patrick Shanahan wrote:
> * Carlos E. R. <> [09-18-17 09:49]:

>>> but...
>>>
>>> my intel based mb specifys 24gig ram but I have 32 and from two different
>>> specs.  this boundary spec is not always updated when motherboards/bioses
>>> receive changes.  you could *try* more ram
>>
>> No, I remember the specs, max is 8.
>
> you misunderstand.  the "specs" are not always correct for your mb,
> usually the max which matches all, not necessarily the max for you mb.
> try more, it will complain or fault if not usable.  try more ram.  
The specs of my mb specify 8 MiB. I'm not going to spend the money on
more with a 95% chance of wasting it.

If I had it on a drawer, I'd try.

--
Cheers / Saludos,

                Carlos E. R.

  (from 42.2 x86_64 "Malachite" (Minas Tirith))


signature.asc (220 bytes) Download Attachment
Reply | Threaded
Open this post in threaded view
|

Re: I need more ram, but I can't.

Carlos E. R.-2
In reply to this post by gregfreemyer
On 2017-09-18 18:28, Greg Freemyer wrote:

> Is this a desktop?  If so, for ~$20 you can buy a NVMe SSD controller
> card.  It fits into a PCIe slot.  (Assuming you have an empty slot).

I have free slots, yes, but I don't remember the kind.


> NVMe SSDs scream.  Mine benchmarks above 1.5 GB/sec.  (That's B for
> Bytes, not b for bits).  I have openSUSE 42.2 running on it.  But I
> have plenty of RAM, so I don't think the PC ever swaps.
>
> Not as fast as RAM, but 10x the speed of rotating drives even if you
> ignore seek times.
>
> I have 2 of the NVMe SSDs.  One was way expensive (2 TB).
>
> But the Samsung PM951 128GB is under $100.
Interesting, very interesting. Does one need both a controller card and
the SSD?



The thing is, when I restore from hibernation I see apps swapping in
(back to ram), recovering. For instance, Thunderbird was recovering at
600K/S, according to iotop. Total disk flow was under 2MB/S, according
to gkrellm. I'm this instant using the laptop, which disk is capable of
about 50 MB/S. Why does Leap recover so slowly from hibernation? It
takes minutes till I can really use the machine. 13.1 did the same thing
way much faster.

--
Cheers / Saludos,

                Carlos E. R.

  (from 42.2 x86_64 "Malachite" (Minas Tirith))


signature.asc (220 bytes) Download Attachment
Reply | Threaded
Open this post in threaded view
|

Re: I need more ram, but I can't.

Carlos E. R.-2
In reply to this post by Lew Wolfgang
On 2017-09-18 16:33, Lew Wolfgang wrote:
> On 09/18/2017 06:23 AM, Carlos E. R. wrote:

>> Hi,
>>
>> I need more ram than my 8GiB, but my board doesn't allow it. I use
>> swap, but Leap is very slow when swapping; I have the feeling that it
>> is slower than other releases.
>>
>> So I wonder if there is some type of small hard disk that can be used
>> for fast swap. SSD? Would it wear out? SSD is typically slow at writing.
>
> We've been using SSD's for root and swap partitions on scientific workstations
> and servers since 2008 or so, and we've never had a problem. Indeed, the first
> one I installed is still working after running 24/7 for nine years.
> Writing to SSD's may be slower than reading, but the writing is still MUCH faster than
> writing to spinning disks.  I'd give it a try, Carlos.  Your motherboard does
> support SATA, right?
It does, yes.

I might have a think at using one SSD disk as cache for the rotating
disks. I have four, the smaller is 2TB. Dunno, it is not easy.


> BTW, I installed my latest server a few weeks ago that has 512-GB of ECC RAM,
> and my users have still managed to fill it up and overflow to swap. Yes, SSD
> drives for root and swap too.  Leap 42.3 really screams on it!

You got me drooling. ;-)

--
Cheers / Saludos,

                Carlos E. R.

  (from 42.2 x86_64 "Malachite" (Minas Tirith))


signature.asc (220 bytes) Download Attachment
Reply | Threaded
Open this post in threaded view
|

Re: I need more ram, but I can't.

Carlos E. R.-2
In reply to this post by Anthony Youngman
On 2017-09-18 17:28, Wols Lists wrote:

> The other thing is, depending on the PC, might it be simpler to just
> upgrade the mobo? I guess you're on DDR2? My DDR3 mobo is 16GB.

I don't remember, and "hwinfo --memory" does not say. I think it is DDR3.

> And I'm
> looking at upgrading - the new setup will take 4 x 8 or 16 GB sticks,
> and the cost will be about £150 plus ram (£50 for the mobo, £100 for the
> processor, ram maybe £30 a stick?) My current machine is probably a good
> five years old, if not more ...

Well, it never is only the board. Board, ram, cpu, at least. My board is
a good one, and at the time I thought 8 GiB would last long.


--
Cheers / Saludos,

                Carlos E. R.

  (from 42.2 x86_64 "Malachite" (Minas Tirith))


signature.asc (220 bytes) Download Attachment
Reply | Threaded
Open this post in threaded view
|

Re: I need more ram, but I can't.

Anton Aylward-2
In reply to this post by Carlos E. R.-2
On 18/09/17 05:19 PM, Carlos E. R. wrote:
> On 2017-09-18 17:06, Knurpht - Gertjan Lettink wrote:
>> Op maandag 18 september 2017 15:56:59 CEST schreef Patrick Shanahan:
>>>> No, I remember the specs, max is 8.
>>
>> So was my old server/workstation. A BIOS update and now the max is 16 GB.
>
> Huh. The MB has some years and I don't remember updates available. If
> there were updates for the amount of RAM, I'd noticed.
>

Possibly; possibly not.
I never saw a notice for the update to the BIOS for my Dell.
The 'Net says it is a 4G system.
A friend told me there was a BIOS update but he hadn't applied it, although he
runs with 16G.
How come?  He says it just works out that way.  Any more in the 4 slots would
need 8G DDR2, and that VERY expensive and rare.  I'm not even sure that the
channel controllers and the MB wiring would allow for that.

--
         A: Yes.
     >   Q: Are you sure?
     >>  A: Because it reverses the logical flow of conversation.
     >>> Q: Why is top posting frowned upon?


--
To unsubscribe, e-mail: [hidden email]
To contact the owner, e-mail: [hidden email]

Reply | Threaded
Open this post in threaded view
|

Re: I need more ram, but I can't.

Carlos E. R.-2
In reply to this post by John Andersen-2
On 2017-09-18 19:56, John Andersen wrote:
> On 09/18/2017 06:23 AM, Carlos E. R. wrote:

>
> Another few points to consider Carlos:
>
> Sometimes you think you are using swap, but you check and find out that the machine is set up
> by default to resist swapping until it gets desperate for memory.  This has been the trend lately
> but it is a silly default when you have swap on an SSD.
>
> I'm currently running 42.2 on a laptop limited to 4gig. I crank up the swappiness (60) and crank
> down the cache pressure (50). I WANT it to swap.  I want it to swap early and often.
>
> Its using 4 gig of memory with a 6gig swap on SSD in a dual core machine.
> Sometimes running VMs I'm using more swap space than I am real memory. Its fast as hell.
>
> In /etc/sysctl.conf
> vm.swappiness = 60
> vm.vfs_cache_pressure = 50
>
> I make much more use of swap this way than with the default settings.
Oh, I know I use swap. On the laptop:

top - 23:45:17 up 9 days, 10:29,  3 users,  load average: 0.19, 0.33, 0.79
Tasks: 285 total,   2 running, 282 sleeping,   0 stopped,   1 zombie
%Cpu(s):  6.1 us,  2.1 sy,  0.1 ni, 91.0 id,  0.4 wa,  0.0 hi,  0.1 si,  0.0 st
KiB Mem:   3947076 total,  3362332 used,   584744 free,   118484 buffers
KiB Swap:  6289412 total,  1458472 used,  4830940 free.  1810508 cached Mem
                           ********


Desktop (rebooted today, so not many tasks)

top - 23:46:05 up  8:18,  3 users,  load average: 0.59, 0.48, 0.54
Tasks: 462 total,   2 running, 459 sleeping,   0 stopped,   1 zombie
%Cpu(s): 11.2 us,  1.8 sy,  0.0 ni, 87.0 id,  0.0 wa,  0.0 hi,  0.0 si,  0.0 st
KiB Mem:   8174404 total,  7330220 used,   844184 free,   488952 buffers
KiB Swap: 43744244 total,  1211500 used, 42532744 free.  3275364 cached Mem
                           *******

I have seen swap at 4 Gigs. When you hibernate, everything goes to swap. The problem is, Leap recovers very slowly. Takes minutes.
changing workplace in XFCE to use LOffice, and I have to wait minutes for it to respond.


> Now about your worry regarding write to SSD....  Yes write is slower than read.
> But only because Read is so blindingly fast.
> Writing on ssd is light years ahead of HDD write speeds.  You can only call it slow when viewed in
> comparison to the same SSD's read speed.
>
> So don't be afraid to write on your SSD, and don't be afraid to use the hell out of your SSD.  You
> will send the machine to recycle long before your ssd wears out.
>
> Another possible source of slowness:  discard option in fstab.
> You want to remove that from every partition in fstab that sits on ssd.
> Instead use systemd's fstrim.timer.
Ah.

>
> sudo systemctl enable fstrim.timer
> sudo systemctl start fstrim.timer
> sudo systemctl status fstrim.service
>
> This will trim you drives once a week (which is plenty) rather than inserting trim
> operations after ever file delete operation. Discard in the fstab entry can make the machine
> "feel" slow and causes excess SSD access.

Interesting.

>
> One recommendation for swap on ssd (or any partition on ssd) is to over provision, provide more
> space than you actually need so as not to force trim operations for space recovery. Ned 8 gig?
> then partition for 10.

On the one computer with an SSD, I left space not partitioned.

>
> Some links I've found on this subject:
>
> http://www.linux-magazine.com/Issues/2016/187/SSD-tuning
>
> Somewhat dated: Mostly from Ted Ts'o who knows a thing or two about file systems:
> https://thunk.org/tytso/blog/2009/02/22/should-filesystems-be-optimized-for-ssds/
> Newer post by Ted Ts'o on this:
> https://forums.freebsd.org/threads/56951/#post-328912
>
> Also Less specific:
> https://arstechnica.com/gadgets/2015/04/ask-ars-my-ssd-does-garbage-collection-so-i-dont-need-trim-right/
>
> ArchWiki also recommends against discard:
> https://wiki.archlinux.org/index.php/Solid_State_Drives
>
> Also, (side issue  nothing to do with swap) btrfs is not really optimized for ssd.
> https://btrfs.wiki.kernel.org/index.php/FAQ#Is_Btrfs_optimized_for_SSD.3F
Thanks for the links.
No, I stay away from btrfs. I use ext4, xfs, and some reiserfs.

--
Cheers / Saludos,
               
                Carlos E. R.

  (from 42.2 x86_64 "Malachite" (Minas Tirith))


signature.asc (220 bytes) Download Attachment
Reply | Threaded
Open this post in threaded view
|

Re: I need more ram, but I can't.

Carlos E. R.-2
In reply to this post by Carlos E. R.-2
On 2017-09-18 23:43, Carlos E. R. wrote:
> On 2017-09-18 17:28, Wols Lists wrote:
>
>> The other thing is, depending on the PC, might it be simpler to just
>> upgrade the mobo? I guess you're on DDR2? My DDR3 mobo is 16GB.
>
> I don't remember, and "hwinfo --memory" does not say. I think it is DDR3.

Quad-Kit DIMM 8 GB DDR3-1333, looking at the purchase order (Oct 2009).

--
Cheers / Saludos,

                Carlos E. R.

  (from 42.2 x86_64 "Malachite" (Minas Tirith))


signature.asc (220 bytes) Download Attachment
1234 ... 8