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.
Best, -at
From: Aleksey Tsalolikhin atsaloli.tech@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
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.
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
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.
On Thu, Sep 22, 2011 at 12:37 PM, John R Pierce pierce@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.
On 09/22/2011 06:20 AM, Rudi Ahlers wrote:
On Thu, Sep 22, 2011 at 12:37 PM, John R Pierce pierce@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.
On 09/22/2011 06:20 AM, Rudi Ahlers wrote:
On Thu, Sep 22, 2011 at 12:37 PM, John R Pierce pierce@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.
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 different philosophies about several things; I like having the choice, and I like it that SL and CentOS are different. Different is not a bad thing.
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.
On Sep 22, 2011, at 10:32 AM, fred smith fredex@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
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/
-- Nux! www.nux.ro
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