Re: [CentOS] How to update CentOS 5.4 to 5.6?

2011-09-23 Thread Rudi Ahlers
On Thu, Sep 22, 2011 at 12:37 PM, John R Pierce pie...@hogranch.com wrote:
 On 09/22/11 3:08 AM, Sebastian Schubert wrote:
 Am 22.09.11 11:59, schrieb John R Pierce:
   On 09/22/11 2:13 AM, John Doe wrote:
   If you want to take the risk anyway, the following (untested) might 
  work:
   Modify your /etc/yum.repos.d/CentOS-Base.repo
   try to replace the baseurl's $releasever with 5.6...
 
   no, as the 5.6 specific files are removed when 5.7 is released. you'd
   have to get a clone of the vault's 5.6 directory and set that up as a
   local repository instead, then point the repo file to that.
 crap ... the 5.6 files are still there .. just change the baseurl like
 john doe wrote and you'll get an update to 5.6

 no, they aren't.

 http://mirror.centos.org/centos/5.6/

 empty.  except a readme file telling you to look in /5/ instead, which
 has the 5.7 stuff in it.




Why would the 5.6 stuff have been removed?

Apart from the 5.7 is more secure answer, or even we're running out
of disk space, what is the actual reason behind this?

surely a few versions of the OS won't take up that much space? 1TB 
2TB HDD's these day cost a few dollars so I don't think that's the
real reason. And it can't be bandwidth either since the files are
mirrored to many other servers around the globe.


-- 
Kind Regards
Rudi Ahlers
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Website: http://www.SoftDux.com
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Re: [CentOS] How to update CentOS 5.4 to 5.6?

2011-09-23 Thread fred smith
On Thu, Sep 22, 2011 at 03:37:38AM -0700, John R Pierce wrote:
 On 09/22/11 3:08 AM, Sebastian Schubert wrote:
  Am 22.09.11 11:59, schrieb John R Pierce:
On 09/22/11 2:13 AM, John Doe wrote:
If you want to take the risk anyway, the following (untested) might 
   work:
Modify your /etc/yum.repos.d/CentOS-Base.repo
try to replace the baseurl's $releasever with 5.6...
  
no, as the 5.6 specific files are removed when 5.7 is released. you'd
have to get a clone of the vault's 5.6 directory and set that up as a
local repository instead, then point the repo file to that.
  crap ... the 5.6 files are still there .. just change the baseurl like
  john doe wrote and you'll get an update to 5.6
 
 no, they aren't.
 
 http://mirror.centos.org/centos/5.6/
 
 empty.  except a readme file telling you to look in /5/ instead, which 
 has the 5.7 stuff in it.

I'm joining this thread late, so pls forgive me if I'm repeating anything
that someone else has already said.

One relatively easy way to do what I think the OP requests is to go to
vault.centos.org, download the appropriate 5.6 ISO, burn to suitable
optical media, boot, and run an UPDATE installation.

YMMV.

-- 
 Fred Smith -- fre...@fcshome.stoneham.ma.us -
   I can do all things through Christ 
  who strengthens me.
-- Philippians 4:13 ---
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Re: [CentOS] How to update CentOS 5.4 to 5.6?

2011-09-23 Thread nux
Aleksey Tsalolikhin writes:

 Is there a way to update a CentOS 5.4 server to 5.6 (but not 5.7)?
 
 yum update takes me all the way up to 5.7.
 

Use the 5.6 repos from the vault in your yum configs:
http://vault.centos.org/5.6/

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Nux!
www.nux.ro

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Re: [CentOS] How to update CentOS 5.4 to 5.6?

2011-09-23 Thread Johnny Hughes
On 09/22/2011 06:20 AM, Rudi Ahlers wrote:
 On Thu, Sep 22, 2011 at 12:37 PM, John R Pierce pie...@hogranch.com wrote:
 On 09/22/11 3:08 AM, Sebastian Schubert wrote:
 Am 22.09.11 11:59, schrieb John R Pierce:
  On 09/22/11 2:13 AM, John Doe wrote:
  If you want to take the risk anyway, the following (untested) might 
 work:
  Modify your /etc/yum.repos.d/CentOS-Base.repo
  try to replace the baseurl's $releasever with 5.6...

  no, as the 5.6 specific files are removed when 5.7 is released. you'd
  have to get a clone of the vault's 5.6 directory and set that up as a
  local repository instead, then point the repo file to that.
 crap ... the 5.6 files are still there .. just change the baseurl like
 john doe wrote and you'll get an update to 5.6

 no, they aren't.

 http://mirror.centos.org/centos/5.6/

 empty.  except a readme file telling you to look in /5/ instead, which
 has the 5.7 stuff in it.

 
 
 
 Why would the 5.6 stuff have been removed?
 
 Apart from the 5.7 is more secure answer, or even we're running out
 of disk space, what is the actual reason behind this?
 
 surely a few versions of the OS won't take up that much space? 1TB 
 2TB HDD's these day cost a few dollars so I don't think that's the
 real reason. And it can't be bandwidth either since the files are
 mirrored to many other servers around the globe.
 
 

They are removed because they do take up too much disk space.

The CentOS project has to maintain dozens of servers as mirrors/rsync
machines.  We have to sync to hundreds of external (that is, not
maintained by the CentOS Project ... but can be used by CentOS users)
mirrors

All of our internal (the ones maintained by the CentOS Project) Mirror
servers are donated by hosting providers and we only get what they are
willing to donate.  If they give us a machine with a 1 TB drive, great.
 If it has 500GB, that is what we get.  Some of them upgrade us, some
don't.  We can only have a repository to mirror that is as large as
the smallest drive on the machines we want to use a a mirror.

As we increase the size of the repo, we drop more and more machines out
of the list of machines we can use a mirror/rsync machines.  Not to
mention that we eliminated people externally who can mirror CentOS for
users.

You have to remember that there are millions of CentOS machines that
update and we have to not provide 1 location that contains all the
files, but enough locations available that contain all of the files to
serve several million users.

So, you say, just upgrade the machines to a bigger hard drive.  Well
that is much harder than you would imagine.  First off, they are not OUR
machines.  Secondly, if they were OUR machines, we would need to buy the
drives and pay someone to install them as we have machines all over the
world.  (As a side note, we are managing internal CentOS Project
machines in 12 countries on 5 continents)

If you wanted to upgrade 250 servers, and if you wanted to pay $200.00
each for one of those cheap hard drive to do it ... then that would be:

250 x $200.00 = $50,000.00

I don't know about you ... but I can't write a $50K check to make that
happen.  If you can, I'll send you my address.

Even if we DID have the space on the CentOS machines, there would be the
time (and bandwidth) required to stand up a new mirror or to maintain
all the old mirrors.  This gets significantly longer if we maintain all
the trees on all the servers.  The vast majority of requests are only
for the latest tree ... but the releases would be significantly delayed
to move around old trees.

So, we only mirror as installable, the latest of each of the supported
versions.  The rest we maintain available in archive at
vault.centos.org.  You can download and use those yourself if you want
to do so.





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Re: [CentOS] How to update CentOS 5.4 to 5.6?

2011-09-23 Thread Johnny Hughes
On 09/22/2011 06:20 AM, Rudi Ahlers wrote:
 On Thu, Sep 22, 2011 at 12:37 PM, John R Pierce pie...@hogranch.com wrote:
 On 09/22/11 3:08 AM, Sebastian Schubert wrote:
 Am 22.09.11 11:59, schrieb John R Pierce:
  On 09/22/11 2:13 AM, John Doe wrote:
  If you want to take the risk anyway, the following (untested) might 
 work:
  Modify your /etc/yum.repos.d/CentOS-Base.repo
  try to replace the baseurl's $releasever with 5.6...

  no, as the 5.6 specific files are removed when 5.7 is released. you'd
  have to get a clone of the vault's 5.6 directory and set that up as a
  local repository instead, then point the repo file to that.
 crap ... the 5.6 files are still there .. just change the baseurl like
 john doe wrote and you'll get an update to 5.6

 no, they aren't.

 http://mirror.centos.org/centos/5.6/

 empty.  except a readme file telling you to look in /5/ instead, which
 has the 5.7 stuff in it.

 
 
 
 Why would the 5.6 stuff have been removed?
 
 Apart from the 5.7 is more secure answer, or even we're running out
 of disk space, what is the actual reason behind this?
 
 surely a few versions of the OS won't take up that much space? 1TB 
 2TB HDD's these day cost a few dollars so I don't think that's the
 real reason. And it can't be bandwidth either since the files are
 mirrored to many other servers around the globe.
 
 

As far as the amount of data that we are talking about ...

3 releases (4.9, 5.7, 6.0) are right now 105GB.

So that is 35GB per tree.

If you just did that same amount for 9 version 4's, 7 version 5's and 3
version 6's ... that would be 19 ... so lets call it 20 ... trees.

20 x 35 GB is 700GB

or ~7x the amount we currently have

It would also take 7x more bandwidth and 7x more time to move the trees
around.




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Re: [CentOS] How to update CentOS 5.4 to 5.6?

2011-09-23 Thread Ross Walker
On Sep 22, 2011, at 10:32 AM, fred smith fre...@fcshome.stoneham.ma.us wrote:

 On Thu, Sep 22, 2011 at 03:37:38AM -0700, John R Pierce wrote:
 On 09/22/11 3:08 AM, Sebastian Schubert wrote:
 Am 22.09.11 11:59, schrieb John R Pierce:
 On 09/22/11 2:13 AM, John Doe wrote:
 If you want to take the risk anyway, the following (untested) might 
 work:
 Modify your /etc/yum.repos.d/CentOS-Base.repo
 try to replace the baseurl's $releasever with 5.6...
 
 no, as the 5.6 specific files are removed when 5.7 is released. you'd
 have to get a clone of the vault's 5.6 directory and set that up as a
 local repository instead, then point the repo file to that.
 crap ... the 5.6 files are still there .. just change the baseurl like
 john doe wrote and you'll get an update to 5.6
 
 no, they aren't.
 
 http://mirror.centos.org/centos/5.6/
 
 empty.  except a readme file telling you to look in /5/ instead, which 
 has the 5.7 stuff in it.
 
 I'm joining this thread late, so pls forgive me if I'm repeating anything
 that someone else has already said.
 
 One relatively easy way to do what I think the OP requests is to go to
 vault.centos.org, download the appropriate 5.6 ISO, burn to suitable
 optical media, boot, and run an UPDATE installation.

Easier still would have the OP add the 5.6 vault URL in his repo file and do a 
yum update off it.

-Ross

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Re: [CentOS] How to update CentOS 5.4 to 5.6?

2011-09-23 Thread Lamar Owen
On Thursday, September 22, 2011 07:20:15 AM Rudi Ahlers wrote:
 surely a few versions of the OS won't take up that much space? 1TB 
 2TB HDD's these day cost a few dollars so I don't think that's the
 real reason. And it can't be bandwidth either since the files are
 mirrored to many other servers around the globe.

You have the two pieces to the puzzle; put them together.  Many other servers 
times a few dollars equals many more than a few dollars.

Enterprise grade 1TB disks are not a few dollars.  And I for one don't want the 
master copy of CentOS sitting on consumer-cheap drives.  This being the 
Community *ENTERPRISE* Operating System, after all. of course, the 
following is mildly off-topic, but if being *enterprise* is important

To make things even halfway reliable with 1TB drives you need RAID 6; this will 
require 4 drives at minimum to make it worthwhile.  Better is a RAID6 with 8 
500GB drives, as rebuild time will be less when a drive faults (I don't say 
if for a failure, it is mostly surely when).  

Double faults on RAID 5 become a serious issue with larger drives; RAID 6 
handles double faults with any two drives (RAID1/0 can handle some double 
faults, but not all).  There are a number of online articles about these 
things.  Triple parity will soon enough be required, and arrays that can 
operate in degraded mode with no performance hit or data loss will just about 
have to be required.

RAID5/1 can work fairly well, but you need six disks to make that worthwhile.  

Hot-sparing is a necessity with arrays of this size and larger, as hot-sparing 
when a drive shows signs of impending fault is much less wearing on the 
non-faulted drives of the array (which may fault during the rebuild, which is a 
Bad Thing), and it is faster to copy to a hot-spare from the soon-to-be-faulted 
drive than it is to rebuild.  

Reliable fault prediction without many false positives does require specialized 
firmware on the drive to do right; that's part of what you pay for when you buy 
a drive from a vendor such as EMC or NetworkAppliance.  And that's just part of 
the reason that a drive on the 1TB range from one of those vendors is typically 
over $1,000 (typical fibre-channel costs are $2,500 for the current middle of 
the road drives; the new SAS drives being used aren't that much less 
expensive).  With an enterprise array you also get background verify 
(scrubbing) that keeps check on the health of the system and ferrets out 
unrecoverable errors more reliably than consumer hardware PC-based systems do.  

The dirty little secret of hard drives is that errors are occurring in drive 
reads all the time; that's why there is ECC on every sector processed by the 
drive (enterprise arrays typically do this ECC on the controller and not on the 
drive, using 520- or 522- byte sector drives).  Many sectors on the drive will 
error on reads; ECC catches the vast majority; it's when the ECC fails that you 
get a retry, and the TLER value is used for multiple retries and waits, and 
when those all fail you get an unrecoverable error (failure on write will cause 
a remap).  

Consumer drives won't necessarily report those correctable errors, and they 
will try far longer to read the data than an enterprise drive designed for 
array use will. Enterprise drives are expected to report sector health 
completely and accurately to the controller, which then makes the decision to 
remap or to fault; consumer drives will present 'I'm totally perfect' while 
hiding the error from the OS (some even hide errors from the SMART data; I'll 
not mention a vendor, but I have seen drives that reported but a few remaps 
that when surface-tested had many thousands of URE's).

Solid State Drives are more reliable, especially in a read-mostly situation, 
but 1TB worth of SSD is quite expensive.  But they have their own problems.

Adding a terabyte or two to an existing enterprise-class array is far more than 
a few dollars; a few years ago when I purchased some 750GB drives for an array 
I spent $2,500 per drive for five drives ($12.5K); these were added to an 
existing five drives that had been in RAID5, but were expanded to RAID6.  This 
added 2.5TB or so to the array (a 750GB drive will not hold 750GB of data, of 
course; that's the raw capacity; the actual data capacity is in the 690GB 
range; converting from RAID5 to RAID6 effectively spent one full drive on the 
second parity that makes RAID6 do its thing, so effectively I added 4*690GB or 
so of storage).  That's a wonderful ~$5,000 per terabyte of actual usable 
storage that is many times more reliable than a single $100 1TB drive would be.

Now, on to the other issue.  If you want a 5.6 that stays there (and gets 
security-only updates without going to the next point release), you really 
should go to Scientific Linux, since they do exactly that.  That's one of the 
differences between SL and CentOS, so you do have a choice.  Both are quality 
EL rebuilds with 

Re: [CentOS] How to update CentOS 5.4 to 5.6?

2011-09-22 Thread John Doe
From: Aleksey Tsalolikhin atsaloli.t...@gmail.com

 Is there a way to update a CentOS 5.4 server to 5.6 (but not 5.7)?
 yum update takes me all the way up to 5.7.

First, this is normal; yum update will always take you to the most recent 5.x
Second, you will miss important security/bug fixes by staying at 5.6!
If you want to take the risk anyway, the following (untested) might work:
Modify your /etc/yum.repos.d/CentOS-Base.repo
try to replace the baseurl's $releasever with 5.6...

JD
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Re: [CentOS] How to update CentOS 5.4 to 5.6?

2011-09-22 Thread John R Pierce
On 09/22/11 2:13 AM, John Doe wrote:
 If you want to take the risk anyway, the following (untested) might work:
 Modify your /etc/yum.repos.d/CentOS-Base.repo
 try to replace the baseurl's $releasever with 5.6...

no, as the 5.6 specific files are removed when 5.7 is released. you'd 
have to get a clone of the vault's 5.6 directory and set that up as a 
local repository instead, then point the repo file to that.



-- 
john r pierceN 37, W 122
santa cruz ca mid-left coast

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Re: [CentOS] How to update CentOS 5.4 to 5.6?

2011-09-22 Thread Sebastian Schubert
Am 22.09.11 11:59, schrieb John R Pierce:
 On 09/22/11 2:13 AM, John Doe wrote:
 If you want to take the risk anyway, the following (untested) might work:
 Modify your /etc/yum.repos.d/CentOS-Base.repo
 try to replace the baseurl's $releasever with 5.6...

 no, as the 5.6 specific files are removed when 5.7 is released. you'd
 have to get a clone of the vault's 5.6 directory and set that up as a
 local repository instead, then point the repo file to that.

crap ... the 5.6 files are still there .. just change the baseurl like 
john doe wrote and you'll get an update to 5.6
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Re: [CentOS] How to update CentOS 5.4 to 5.6?

2011-09-22 Thread John R Pierce
On 09/22/11 3:08 AM, Sebastian Schubert wrote:
 Am 22.09.11 11:59, schrieb John R Pierce:
   On 09/22/11 2:13 AM, John Doe wrote:
   If you want to take the risk anyway, the following (untested) might 
  work:
   Modify your /etc/yum.repos.d/CentOS-Base.repo
   try to replace the baseurl's $releasever with 5.6...
 
   no, as the 5.6 specific files are removed when 5.7 is released. you'd
   have to get a clone of the vault's 5.6 directory and set that up as a
   local repository instead, then point the repo file to that.
 crap ... the 5.6 files are still there .. just change the baseurl like
 john doe wrote and you'll get an update to 5.6

no, they aren't.

http://mirror.centos.org/centos/5.6/

empty.  except a readme file telling you to look in /5/ instead, which 
has the 5.7 stuff in it.





-- 
john r pierceN 37, W 122
santa cruz ca mid-left coast

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