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Today's Topics:
1. Re: Bristol Digest, Vol 588, Issue 2 (Fergus Allan)
2. Re: Bristol Digest, Vol 588, Issue 2 (Alex Butcher)
3. Backup email servers (Allen Coates)
4. Re: Backup email servers (Alex Butcher)
----------------------------------------------------------------------
Message: 1
Date: Tue, 3 Feb 2015 13:23:31 -0000
From: "Fergus Allan" <f_w_allan@yahoo.co.uk>
To: <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Bristol Digest, Vol 588, Issue 2
Message-ID: <029301d03fb4$9b33f0c0$d19bd240$@yahoo.co.uk>
Content-Type: text/plain; charset="us-ascii"
Hi,
SSD's have been incredibly unreliable. Either dirty pages returned or
complete failure.
I've had 2 crucial SSD's, both failed totally at 3 months old; little red
light comes on and no access to any part of the disk. The first also
returned dirty pages pretty much from day 1. I've haven't fixed all my
corrupted data from that issue. That was a few years ago. We were
discussing ordering some SSDs at work and I suggested Crucial even though I
don't trust their devices, expecting a positive reaction, but they shot
that down as too unreliable.
OCZ went bust and was bought out and the brand name retained. As far as I
can tell, OCZ makes crucial look good for reliability.
22 years? Not a chance. 3 maybe and back up often.
I'm toying with using SSD's again, but can't quite trust them unless I raid
them.
The SSD interface is a hard drive interface so can be directly substituted
for a hard drive and as a boot device. Performance wise, you need to be
aware of TRIM and of the block size. Whilst a modern operating system uses
a 4k block size, the minimum hardware block size in the SSD is 64k last time
I checked. This is why 4k random writes pan the performance.
In short, you want to make sure the disk tracks start on a 64k multiple to
get the best performance.
If not aligned correctly, if you OS is writing a cluster to borrow from
windows, you could write 8k of data that hits 2 different hardware blocks in
the device.
Fergus.
-----Original Message-----
From: bristol-bounces@mailman.lug.org.uk
[mailto:bristol-bounces@mailman.lug.org.uk] On Behalf Of
bristol-request@mailman.lug.org.uk
Sent: 02 February 2015 14:21
To: bristol@mailman.lug.org.uk
Subject: Bristol Digest, Vol 588, Issue 2
Send Bristol mailing list submissions to
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When replying, please edit your Subject line so it is more specific than
"Re: Contents of Bristol digest..."
Today's Topics:
1. Boot using an SSD? (Mik Phelps)
2. Re: Boot using an SSD? (David Smith)
3. Re: Boot using an SSD? (Adrian Portway)
4. Re: Pi - SSH apt-get problem (Martin Habets)
5. Re: Boot using an SSD? (Alex Butcher)
6. Re: Boot using an SSD? (Shane McEwan)
7. Re: Boot using an SSD? (David Smith)
----------------------------------------------------------------------
Message: 1
Date: Mon, 02 Feb 2015 12:15:18 +0000
From: Mik Phelps <ha1ry.g1t@mypostoffice.co.uk>
To: bristol@mailman.lug.org.uk
Subject: [bristol] Boot using an SSD?
Message-ID: <54CF6A56.1040600@mypostoffice.co.uk>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Hi all
I haven't posted on here for a while but I have been watching things
whenever I get a notification Email.
Please can I ask for advice about having the Linux Boot Sector, plus a
couple of other things, on an SSD drive, since I remember something about
this not being necessarily easy but I can't find the earlier thread(s) on
here about this.
First OS to be openSUSE 13.2 64bit, deliberately not a 'bleeding edge'
Distro so that it's a bit more hardened rather than using the very latest
versions.
This completed Workstation is for the 'usual' daily office type things, some
Electronics and Loudspeaker Design related CAD plus remote control (GPIB and
Serial) of Electronics measurement/test Instruments on my bench with good
results viewing/comparisons amongst other things.
A possible second OS is still to be decided on, but may well be one of the
more specialised Linux 'Scientific Distros'.
So this is for a 'new build' PC with an i5-4690 processor, asus B65 Pro
Gamer Intel chipset Motherboard, 32GB DDR3 1333ram, Matrox dual head
Graphics Card with two Dell U2412M monitors to start with, The Asus MB is
because I need all three older type PCI expansion slots and Motherboards
with these type and number of expansion slots are getting really difficult
to find!
First Hard disk to be a fast R/W SSD, Samsung 850 EVO 120GB, with '/' type
partition for the OS plus a partition for 'swap', and then hopefully the
Boot Sector as well?
Second Hard disk for now , as I might add more for a software RAID setup
later, to be a WD, HDD RE4 500Gb, high reliability Server type, with the
entire disk to be partitioned for '/Home'.
Which is where my (first?) question arises about the Boot Sector please.
All parts have arrived where it is being assembled and tested together with
other necessary bits and bobs, such as two CD/DVD R/W drives, Etc to be
included in this build as well.
This is my last year's 65th Birthday and Christmas present to myself and if
it lasts as long as this
22+ year old Evesham Pentium 1 which I'm typing out this Post on, then
22+ it will both certainly 'see
me out' plus hopefully will give someone else some pleasure using it after
me :-) Anyway, much like me the Evesham is showing it's age with various
things beginning to fail with old age.
Thanks in advance for your valued assistance
yours
Mik
------------------------------
Message: 2
Date: Mon, 2 Feb 2015 12:24:58 +0000
From: David Smith <David.Smith@imgtec.com>
To: Bristol and Bath Linux User Group <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Boot using an SSD?
Message-ID:
<15A9D35B5490FC49AC0524AE3A085F0888984B@BRMAIL01.br.imgtec.org>
Content-Type: text/plain; charset="us-ascii"
From: bristol-bounces@mailman.lug.org.uk [mailto:bristol-
bounces@mailman.lug.org.uk] On Behalf Of Mik Phelps
> Please can I ask for advice about having the Linux Boot Sector, plus
> a couple of other things, on an SSD drive, since I remember something
> about this not being necessarily easy but I can't find the earlier
thread(s) on here about this.
I don't see why it should be difficult - my Asus Eee is SSD-only, and the OS
install is/was pretty easy.
------------------------------
Message: 3
Date: Mon, 02 Feb 2015 12:41:13 +0000
From: Adrian Portway <adrian.portway@gmail.com>
To: Bristol and Bath Linux User Group <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Boot using an SSD?
Message-ID:
<CAAUR1PvXDp-7zWNjCzZJHFR6icTxdaiCe=OCHqMMdx6knNVq-A@mail.gmail.com>
Content-Type: text/plain; charset="iso-8859-1"
I second David's comment. I've been happily installing and booting SSD only
machines ( desktop and server ) for a while without any problems.
On Mon Feb 02 2015 at 12:25:37 David Smith <David.Smith@imgtec.com> wrote:
> From: bristol-bounces@mailman.lug.org.uk [mailto:bristol-
> bounces@mailman.lug.org.uk] On Behalf Of Mik Phelps
> > Please can I ask for advice about having the Linux Boot Sector,
> > plus a
> couple
> > of other things, on an SSD drive, since I remember something about
> > this
> not
> > being necessarily easy but I can't find the earlier thread(s) on
> > here
> about this.
>
> I don't see why it should be difficult - my Asus Eee is SSD-only, and
> the OS install is/was pretty easy.
>
> _______________________________________________
> Bristol mailing list
> Bristol@mailman.lug.org.uk
> https://mailman.lug.org.uk/mailman/listinfo/bristol
>
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Message: 4
Date: Mon, 2 Feb 2015 13:14:18 +0000
From: Martin Habets <errandir_news@mph.eclipse.co.uk>
To: Bristol and Bath Linux User Group <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Pi - SSH apt-get problem
Message-ID: <20150202131418.GB30434@mph.eclipse.co.uk>
Content-Type: text/plain; charset=us-ascii
On Sun, Feb 01, 2015 at 12:29:59AM +0000, Peter Hemmings wrote:
> It was, I ended up removing the relevant files in
> "/var/lib/dpkg/info/" then re-installing them with apt-get install
> XXXXX --reinstall
>
> Also did a "clean" "autoremove" and "update" for good measure but
> maybe that was not necessary. All now OK have motion/camera working
> as well as ssh.
The "clean" will remove those files in /var/lib/dpkg/info/.
Good to see you've got it fixed.
Martin
> >Martin
> >
> >On Sat, Jan 31, 2015 at 05:26:40PM +0000, Peter Hemmings wrote:
> >>Hi,
> >>
> >>I have been playing with a pi "Noir Camera", it works OK on remote
> >>desktop with rdp but am having problems with sshing and getting
> >>apt-get to install programs.
> >>
> >>As this is not my normal distro, could someone help with how to
> >>resolve the errors?:
> >>
> >>
> >>The following packages will be REMOVED:
> >> ssh
> >>0 upgraded, 0 newly installed, 1 to remove and 88 not upgraded.
> >>After this operation, 29.7 kB disk space will be freed.
> >>Do you want to continue [Y/n]? y
> >>dpkg: warning: files list file for package 'lxinput' missing;
> >>assuming package has no files currently installed
> >>dpkg: warning: files list file for package 'python-minimal' missing;
> >>assuming package has no files currently installed
> >>dpkg: unrecoverable fatal error, aborting:
> >> files list file for package 'poppler-utils' is missing final
> >>newline
> >>E: Sub-process /usr/bin/dpkg returned an error code (2)
> >>pi@raspberrypi ~ $
> >>
> >>
> >>Thanks
> >>
> >>--
> >>Peter H
> >>
> >>_______________________________________________
> >>Bristol mailing list
> >>Bristol@mailman.lug.org.uk
> >>https://mailman.lug.org.uk/mailman/listinfo/bristol
> >
> >_______________________________________________
> >Bristol mailing list
> >Bristol@mailman.lug.org.uk
> >https://mailman.lug.org.uk/mailman/listinfo/bristol
> >
>
> Regards
> --
> Peter H
>
> _______________________________________________
> Bristol mailing list
> Bristol@mailman.lug.org.uk
> https://mailman.lug.org.uk/mailman/listinfo/bristol
------------------------------
Message: 5
Date: Mon, 2 Feb 2015 14:06:07 +0000 (GMT)
From: Alex Butcher <lug@assursys.co.uk>
To: Bristol and Bath Linux User Group <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Boot using an SSD?
Message-ID:
<alpine.LFD.2.11.1502021357080.21723@sbhezbfg.of5.nffheflf.cev>
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
On Mon, 2 Feb 2015, Mik Phelps wrote:
> Hi all
> I haven't posted on here for a while but I have been watching things
> whenever I get a notification Email.
>
> Please can I ask for advice about having the Linux Boot Sector, plus
> a couple of other things, on an SSD drive, since I remember something
> about this not being necessarily easy but I can't find the earlier
> thread(s) on here about this.
I can't conceive of any problems with that; SSDs just show up as standard
SATA devices. Remember to configure the BIOS to present them as AHCI before
installing your OS (especially Windows), though. Care to elaborate further
on what you'd heard?
[...]
> So this is for a 'new build' PC with an i5-4690 processor, asus B65
> Pro Gamer Intel chipset Motherboard, 32GB DDR3 1333ram, Matrox dual
> head Graphics Card with two Dell U2412M monitors to start with,
[...]
> First Hard disk to be a fast R/W SSD, Samsung 850 EVO 120GB, with '/'
> type partition for the OS plus a partition for 'swap', and then
> hopefully the Boot Sector as well?
With 32GB of RAM, a) you probably won't need swap and b) you don't want it
on your SSD as the number of writes will age it prematurely.
> Second Hard disk for now , as I might add more for a software RAID
> setup later, to be a WD, HDD RE4 500Gb, high reliability Server type,
> with the entire disk to be partitioned for '/Home'.
WD RAID Edition drives run with Time-Limited Error Recovery enabled by
default, so as to prevent a RAID controller from removing a drive from an
array because of a single failed block causing the drive to perform extended
(>7 seconds) recovery and seeming to the controller to be non-responsive.
TLER relies upon the RAID controller recovering the data from one or more
other drives in the array. If you're only using a single drive, then you
should disable TLER at the very least (but personally, I'd recommend getting
that other drive now and running it in a RAID array as it's designed to be
used).
Also, I'd recommend using LVM and creating a logical volume for /home,
starting at your current /home size plus 10%, say. Then, if you need more
space, extend the logical volume and resize the filesystem. That keeps space
available for other parts of the filesystem should you need it. Partitioning
isn't the most appropriate thing to do with modern, large discs.
> Which is where my (first?) question arises about the Boot Sector please.
What is your question?
> yours
> Mik
HTH,
Alex
------------------------------
Message: 6
Date: Mon, 02 Feb 2015 14:11:09 +0000
From: Shane McEwan <shane@mcewan.id.au>
To: bristol@mailman.lug.org.uk
Subject: Re: [bristol] Boot using an SSD?
Message-ID: <54CF857D.4090209@mcewan.id.au>
Content-Type: text/plain; charset=utf-8
On 02/02/15 12:15, Mik Phelps wrote:
> Hi all
> I haven't posted on here for a while but I have been watching things
> whenever I get a notification Email.
Welcome back!
> Please can I ask for advice about having the Linux Boot Sector, plus
> a couple of other things, on an SSD drive, since I remember something
> about this not being necessarily easy but I can't find the earlier
> thread(s) on here about this.
I can't think of any reason why you couldn't boot of an SSD. BIOS issues,
maybe, but any modern BIOS shouldn't have a problem. I have an Asus laptop
with only SSDs in it and it works fine.
The recommendation is that you turn on TRIM support for wear levelling of
the SSD. You either add the 'discard' option to your SSD mounts in
/etc/fstab (which can slow down file deletes on some SSDs) or add a cron job
that runs 'fstrim' occasionally (daily or weekly).
You should change your IO scheduler to 'noop' or 'deadline' for your SSD
device. The current scheduler is shown in brackets in
'/sys/block/<device>/queue/scheduler' and will probably be 'cfq'. I don't
know SUSE so I'm not sure how to change the scheduler permanently.
Somewhere in 'udev' I suspect. There should be tuning guides for SUSE on the
Internet somewhere.
> First Hard disk to be a fast R/W SSD, Samsung 850 EVO 120GB, with '/'
> type partition for the OS plus a partition for 'swap', and then
> hopefully the Boot Sector as well?
I'm inclined to recommend not bothering with swap. With 32GB of RAM you're
unlikely to start swapping unless you've got some seriously big software
running. The issue with swap on SSDs is that if you do start swapping you're
going to be doing a lot of writes to the SSD which reduces the life of it.
The reality is that modern SSDs are actually very reliable and last a long
time but if you really intend your PC to last 22 years then you're gonna
have to watch your writes to the SSD!
Also, the rule of thumb is to add as much swap as RAM but 32GB is a fair
chunk of your SSD. Do you really want to waste that space just for the
unlikely event of running out of RAM? If you really want swap on your SSD
then I'd recommend turning 'swappiness' down to a low value like '1'. That
will stop the kernel swapping out memory unless you're close to running out.
Have fun with your new toy!
Shane.
------------------------------
Message: 7
Date: Mon, 2 Feb 2015 14:20:32 +0000
From: David Smith <David.Smith@imgtec.com>
To: Bristol and Bath Linux User Group <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Boot using an SSD?
Message-ID:
<15A9D35B5490FC49AC0524AE3A085F088898BC@BRMAIL01.br.imgtec.org>
Content-Type: text/plain; charset="us-ascii"
> From: bristol-bounces@mailman.lug.org.uk [mailto:bristol-
> bounces@mailman.lug.org.uk] On Behalf Of Shane McEwan I'm inclined to
> recommend not bothering with swap. With 32GB of RAM you're unlikely to
> start swapping unless you've got some seriously big software running.
> The issue with swap on SSDs is that if you do start swapping you're
> going to be doing a lot of writes to the SSD which reduces the life of
> it. The reality is that modern SSDs are actually very reliable and
> last a long time but if you really intend your PC to last 22 years
> then you're gonna have to watch your writes to the SSD!
Or stick the swap on the HDD. If you're trying to optimise the speed of the
PC by putting the swap on SSD rather than HDD then you're trying the solve
the wrong problem...
------------------------------
_______________________________________________
Bristol mailing list
Bristol@mailman.lug.org.uk
https://mailman.lug.org.uk/mailman/listinfo/bristol
End of Bristol Digest, Vol 588, Issue 2
***************************************
------------------------------
Message: 2
Date: Tue, 3 Feb 2015 14:56:16 +0000 (GMT)
From: Alex Butcher <lug@assursys.co.uk>
To: Bristol and Bath Linux User Group <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Bristol Digest, Vol 588, Issue 2
Message-ID:
<alpine.LFD.2.11.1502031428510.14987@sbhezbfg.of5.nffheflf.cev>
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
On Tue, 3 Feb 2015, Fergus Allan wrote:
> SSD's have been incredibly unreliable. Either dirty pages returned or
> complete failure.
>
> I've had 2 crucial SSD's, both failed totally at 3 months old; little red
> light comes on and no access to any part of the disk. The first also
> returned dirty pages pretty much from day 1. I've haven't fixed all my
> corrupted data from that issue. That was a few years ago. We were
> discussing ordering some SSDs at work and I suggested Crucial even though I
> don't trust their devices, expecting a positive reaction, but they shot
> that down as too unreliable.
But of course you've got backups you can restore from, right?!?
We make extensive use of SSDs in our centralised storage at work, with no
particular problems. But, of course, we'll almost certainly be using
enterprise kit rather than consumer stuff.
When choosing an SSD for a new desktop, amongst the consumer stuff, the
Samsung 850 PRO SSDs struck me as having appreciably better longevity
ratings (150TBW for the 128GB and 256GB models, 300TBW for the 512GB and
1TB) than most others and with a warranty (10 years) to match.
<http://www.storagereview.com/demystifying_ssd_endurance>
Personally, I still rely on (spinning rust) hard drives in RAID1 for storing
data that's at all important. The SSD is purely to improve responsiveness of
the OS and key applications, and it is backed up regularly to a RAID1 array
(or it will be, when I get round to it!)
> OCZ went bust and was bought out and the brand name retained. As far as I
> can tell, OCZ makes crucial look good for reliability.
>
> 22 years? Not a chance. 3 maybe and back up often.
That depends on the figure for maximum write volume (in TBW) and what your
write activity is like. For an SSD to last 22 years in a "normal
workstation" (<http://ssdendurancetest.com/>) requires specifying for
10-20GB/day of writes, or 80.3-160.6TBW. Only a dozen or so drives from the
two manufacturers you name are rated for over 100TBW:
<http://skinflint.co.uk/?cat=hdssd&xf=1035_OCZ~1035_Crucial~4930_100#xf_top>.
> I'm toying with using SSD's again, but can't quite trust them unless I raid
> them.
TBH, I haven't trusted un-mirrored HDDs since 2002.
> Fergus.
Best Regards,
Alex
------------------------------
Message: 3
Date: Tue, 03 Feb 2015 16:59:31 +0000
From: Allen Coates <linux@cidercounty.org.uk>
To: bristol@mailman.lug.org.uk
Subject: [bristol] Backup email servers
Message-ID: <54D0FE73.8010301@cidercounty.org.uk>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Hi All
For about five months I have been running a small email server, which
handles about a dozen messages a day. My "back-up server" is the
simple email forwarding that came with the DNS account. Currently it is
pointing at my ISP.
However, some persistent spammer has discovered that my backup does not
actually refuse *any* messages at all . . .
So I am looking for an alternative that does an honest-to-goodness SMTP
"bounce" on non-existent email addresses - and preferably will also
handle DNS blacklists.
I have a dynamic IP address - although it hasn't changed in over a year
- so I feel I should have a backup of some sort.
Can somebody recommend an (inexpensive) mail back-up service? Or any
other ideas, short of building a second server and parking it in a
friend's house?
Allen C
------------------------------
Message: 4
Date: Tue, 3 Feb 2015 18:46:12 +0000 (GMT)
From: Alex Butcher <lug@assursys.co.uk>
To: Bristol and Bath Linux User Group <bristol@mailman.lug.org.uk>
Subject: Re: [bristol] Backup email servers
Message-ID:
<alpine.LFD.2.11.1502031841000.14987@sbhezbfg.of5.nffheflf.cev>
Content-Type: text/plain; charset="iso-8859-15"; Format="flowed"
On Tue, 3 Feb 2015, Allen Coates wrote:
> For about five months I have been running a small email server, which handles
> about a dozen messages a day. My "back-up server" is the simple email
> forwarding that came with the DNS account. Currently it is pointing at my
> ISP.
>
> However, some persistent spammer has discovered that my backup does not
> actually refuse *any* messages at all . . .
>
> So I am looking for an alternative that does an honest-to-goodness SMTP
> "bounce" on non-existent email addresses - and preferably will also handle
> DNS blacklists.
The ISP I use (Eclipse) provides SMTP mail delivery for ?4 per month (that
?4 also includes DNS registration and hosting and PHP-enabled webspace).
So the MX record for assursys.co.uk points at their MXs which merely do some
spam filtering then queue the messages for final delivery to my MTA,
whenever it's reachable (i.e. like how Demon Internet used to do it, in the
Good Old Days; presumably they have an internal-only MX record that points
to my MX). My own MX can then bounce messages using its own rules.
I don't know if they'll provide this service without you having a connection
with them, though.
Best Regards,
Alex
------------------------------
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Bristol mailing list
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https://mailman.lug.org.uk/mailman/listinfo/bristol
End of Bristol Digest, Vol 588, Issue 4
***************************************
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