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16

I'll second SvenW's warning about silent failures; if anything, it's a little too good at surviving a drive failure. I've seen the aftermath of a couple of servers that had one drive drop out of a software mirror for some reason (I suspect not coming ready in time after a reboot); everything works fine off the remaining drive until, several months later, ...


16

Some packages are held by more than one repository. The priorities plugin choose packages from the highest-priority repository, excluding duplicate entries from other repos.


14

From what I understand, this error is generated from the priorities plugin as noted by Pawel. In 2009, the maintainer of yum mentioned that he hoped people would not use priorities. To disable the priorities plugin, edit /etc/yum/pluginconf.d/priorities.conf and set enabled = 0. After this change, next time you run yum update, you should not get any ...


10

Poor man's stethoscope: Long'ish screwdriver. Tip on the drive, handle on your ear. Listen to each drive. If either clicks you should be able to quickly isolate it. (Works great with valve-covers on your old cars when listening for valve noise too ;-) ) Of course, this assumes clearance and common sense about where on the drive you touch...


9

After I looked at the source code for apt-mirror, I discovered that apt-mirror has inbuilt abilities to limit the bandwith rate. Just put: set limit_rate 50k In your mirror.list file and it will pass that into wget. However that limit is per thread. So if you have 10 threads, this will be 50k * 10 = 500k. This feature is not documentated at all.


9

This is a udev issue that seems to be specific to Debian and Ubuntu variants. Most of my ZFS on Linux work is with CentOS/RHEL. Similar threads on the ZFS discussion list have mentioned this. See: scsi and ata entries for same hard drive under /dev/disk/by-id and ZFS on Linux/Ubuntu: Help importing a zpool after Ubuntu upgrade from 13.04 to 13.10, device ...


8

Question 1: You're overthinking it. SQL 2005's database mirroring specifications are built into the connection string. You specify both the primary server and the mirror right in the connection string, and the driver tries the servers in order. That's one of the beauties of database mirroring - no client app changes are required. More info here: ...


8

rsync is the standard utility for this: rsync -avz -e ssh source/ user@destServer:/dest/ a For archive, keeps permissions, type stamps, etc. v for verbose e ssh , use over ssh z for compression, if you want that. It won't try to re-compress archive (zip) files. rsync generally comes with Linux distributions. It also meets your requirement of not ...


8

What's your definition of "better"? Will it be faster? Probably. Will it require less power? Yes. Will it be more reliable? Maybe not. Even if a single SSD proves to be more reliable than a single standard hard drive (which is up for debate), your data is still not protected from a single-drive failure like it would be in a RAID1 scenario. Additionally, ...


7

You might also try HTTrack which has, IMO, more flexible and intuitive include/exclude logic. Something like this... httrack "https://example.com" -O ExampleMirrorDirectory \ "-*" \ "+https://example.com/images/*" \ "-*.swf" The rules will be applied in order, and will override previous rules... Exclude everything But include ...


7

RoboCopy is a command line tool provided by Microsoft that can do mirroring. The Wiki page also mentions a GUI.


6

If the question is "why can you not have RAID with a single drive that has error correction", the answer is in the "R" of RAID (Redundant Array of Independent Disks)... There would be no redundancy for disk failure. RAID is not designed to protect against data corruption (as par2 is), it is designed to protect against disk failure. A disk failure on a ...


6

You just need a ZFS mirror. You're guaranteed consistent data based on COW and constant checksumming.


6

An old back-woods mechanic trick can come in handy for this kind of thing. I once saw an old mechanic old a long straight stick hard against the palm of his hand and then press his knuckle up against his ear. He placed the other end of the stick on parts of the engine and could hear which cylinder was not firing correctly. Wood conducts sound well if it has ...


6

You should be able to tell him what you are trying to achieve, and he should be able to tell you what you need. Telling him the specifics of something you don't understand that well, 'Use this software' etc, sounds counter productive to me. From what you said, my instinct would be to use the exact solution that chris_l recommends as the technical solution. ...


5

Looking in the event log, you should have an event from the disk source: Log: System Source: disk Event ID: 7 Message: The device, \Device\Harddisk4\DR3, has a bad block. And then to identify DR3, you find Disk 3 in Disk Management:


5

The order would go like this: Update the secondary server (the one that is not currently serving connections) After it reboots, do a controlled mirroring failover to it Update the primary server (which at this point is no longer serving connections) After it reboots, you can do a controlled failover back to it if you want, but you don't have to. You can ...


5

If : The modification time of your files are right The files are not really big No push can be missed (or there is some kind of backlog processing) You can use find -ctime or file -cnewer to make a list of changed file since the last execution, and copying over only the modified files (Just a glorified differential push). This translated itself quite ...


5

It depends very much on the job at hand. Why do you need file mirroring. Do you want to update something like a website or content repository where it's usually okay to update periodically. Or do you need real time synchronization of data? For periodic asynchronous mirroring of files it is usually sufficient to have a Staging Area that you upload all your ...


5

Personally I always go MD+LVM. It is faster (MD can do parallel reads in RAID1) and it requires only 2 disks (if you do not want to rebuild the mirror after every reboot) and MD is designed just to do RAID, and it does it very well. It is also more flexible. Also I have been burned by LVM. In one case it was LVM striping on HP-UX, (should not happen w/ LVM2 ...


5

There's a big difference between "It should work" and "It will work" and if I was that HP guy I'd have gone with the first statement too, if he'd gone with the second and you'd lost data he could have been in trouble. That said 'it should work' :)


5

If you can install lftp on the server you have SSH to, try its mirror command: mirror -R /path/to/httpdocs /path/to/public_html_on_destination_machine


5

I really am just guessing, but I suspect it might look something like this. rsync --archive --verbose --delete cygwin.com::cygwin-ftp/ /your/local/path/ See: http://sourceware.org/cygwin-apps/package-server.html


5

Specify the details of the mirror and/or proxy in the preseed file. All of the possible preseed values you can use should be provided in the manual for the Ubuntu version you're using, but the keys you're interested in are probably mirror/http/proxy and/or mirror/http/hostname.


4

Presuming that the data you're rsyncing isn't already compressed, turning on compression (-z) will likely help transfer speed, at the cost of some CPU on either end.


4

If you are using SQL 2008 the Backup Task has a lovely "Ignore Databases when the State is not online" option. This bypasses databases in a Restoring/Mirroring state for you. For a SQL 2000 Box you can check the following property on each database SELECT NAME FROM sysdatabases WHERE databasepropertyex(sysdatabases .Name, 'Status') = 'ONLINE' For a SQL ...


4

Here are two command line tools that will set mirroring and display resolution as you need. Mirror usage: mirror [option] Passing more than one option produces undefined behavior. -h Print this usage and exit. -t Toggle mirroring (default behavior) -on Turn Mirroring On -off Turn Mirroring Off -q ...


4

rsync in general will be faster than cp or tar, because rsync only transfers those files which have changed, and with --partial it will only transfer the parts of a file that changed. Having said that, rsync works much better if you know what you're backupping and can arrange things so that rsync doesn't have to do as much work. For example, rotated log ...


4

There are several possibilities. You could script some file replication system like rsync; or you could just share a drive between the two computers, e.g. via SAMBA. Or just use VNC/RDP/etc. to work on one computer while using the other. Then there's no need to push files around.


4

Basically you have 3 possibilities: Let your application push the files to both servers. Asynchronous replication, e. g. rsync every 15 minutes (or less) with a cron job Synchronous replication on file system (e. g. GlusterFS) or block device level (e. g. DRBD). If you use replication on block device level, you need a file system which supports distributed ...



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