(e-mail address removed) (Bob) wrote in
Apparently Promise fixed its problems of a few years back. We got an
evaluation version and it quit working in a week.
Promise has their share of problems. Search this group for "Promise" in
the title and you'll see some. But at the moment I am having no problems
with the bios and drivers for the Ultra133 TX card.
I bought a MB from EPOX years ago and it has functioned flawlessly. I
believe they have a RAID MB. Any comments?
Nope. I'd have to read the EPOX manual for that board model. Somewhere it
should be documented who's RAID chipset EPOX is using, and what it can do.
How else would you recover?
You could recover using disk imaging software to a backup drive, or,
traditional backup software to a backup drive. Each has it's pros and
cons. Backup softare can do differential and icremental backups. Imaging
software does an entire parition or drive at a time.
That's the whole idea - to get out of having to do backups.
A mirrored disk can't easily be made into multiple copies, one to keep on
site, one to send off site. You can't easily take it, put it on another
disk or backup media, and get multiple copies. Basically, there are lots of
things you can easily do with a backup that you can't with a mirrored disk.
What backup utility do you recommend. Win2K has one that came with the
OS - is that good enough?
It depends what you want to do with the backup. Recover some files? Backup
the registry? Win2K backup can do that. But if it is a full system
restore, Win2K backup or any backup program has a long recovery process.
First you need to re-install the OS and drivers. Then you need to restore
the backup. Because you can't recover files that are open, you need to
install into a different directory than the one you are restoring, or you
get file in use conflicts. Restoring individual files is easy with backup
software, but recovering the entire system can be a little tricky.
In comparison, recovering the entire system is easy with a mirrored drive
or disk image software. The both can restore the entire boot partition if
need be in just a few steps. If you have a mirrored drive sitting around,
usually that is the fastest.
Once again I ask, if you are going to do backups, then why have RAID?
See above. The flexiblity for each is different. The recovery methods are
different. The recovery times are different, depending on what you want to
recover. A business will use both methods becausee they can't afford the
downtime if one method fails.
Now that I like. A couple of removable drive bays should do the trick.
Let me be sure I understand this. You are saying I can use the
mirroring function on Win2K Pro to run 2 disks simultaneously and
periodically swap out one of the disks for disaster recovery. Of
course I would put another disk in the place of the one I removed and
let Windows rebuild it.
No. I'm not talking about the software mirroring feature at all. I'm
talking about hardware mirroring built into a card or motherboard. This
should work regardless of what OS you are using. All of my experience is
with hardware mirroring. I wouldn't recommend software mirroring. A lot
of the cases I know of where people tried software mirroring are cases
where they found limitations and couldn't recover their data. You can try
it if you want, but performance will be lower than hardware mirroring, and
there are more limitations than hardware mirroring, since you are relying
on the OS. There are more steps involved in recovering from the mirrored
drive and re-mirroring afterwards. It can be done, but I don't know those
steps so I can't really offer any help with them. Suffice it to say that
whatever mirroring solution you pick, you'll need to test it thoroughly for
a failure / recovery / rebuild cycle for both drives before you trust it.
Before I allowed that to happen, I would want to copy over any data I
had accumulated between the time I pulled the mirror. Then I could let
the system perform the mirror, which I assume would wipe out any
updates I made after I pulled the mirror.
Yes, or, have another drive that you can use to get mirroring working again
ASAP while you get more time to recover any data you need off the previous
drive mirror.
How about 10 GB for example using Win2K mirroring? If it is in
background, who cares how long it takes as long as it is reasonable.
Drive Image Pro takes right at 1 hour with verify turned on for a 10
GB partition copy.
I can't say because it varies a huge amount, depending on the drive speed,
the drive size and the model of RAID controller. HW mirroring in general
will be much faster than SW mirroring. Compaq HW mirroring for 9GB SCSI
drives takes about 30 min to mirror using Compaq Smart array controllers.
IBM servers of the same age and class take hours to mirror the same size
SCSI drive with the IBM array controllers. In the case of the IBM servers,
it's faster to use disk imaging software like Ghost or Drive Image for
backup and recovery than it is to use mirroring. The mirrored drive will
get you booting again quickly, no problem there, but rebuilding the mirror
takes forever on those particular systems. So you see why it's hard to say
how long it's going to take. It varies with every controller card.
But as far as getting
I do not understand what you mean by "if the *system* is important to
me". Of course, everything on disk is important to me.
Some people separate their data and OS. They may not care if the OS is
totally lost and they have to rebuild from scratch. The time spent on a
rebulid may not be important to them, as long as they eventually get back
up and can use their data again. To other people, the downtime costs them
money, and they can't afford to be down for very long. They can't afford
the time it takes to re-install the OS, re-install the drivers, re-install
the apps, recover the backup, and finally get to the data. Saving the time
is worth money to them. So they will spend the extra money on whatever
system they need to recover from a drive failure in less time. Everyone's
different.
Why have the full backup if you have pulled a mirror?
See above. Backups, drive images, and mirrored drives each offer ways to
recover from a drive failure. But they each offer different pros and cons
as well. A backup is the quickest for making multiple copies in different
media formats, and for restoring individual or sets of files, particularly
data. A mirror is the quickest way to recover if the OS drive stops
working for any reason. But with a mirror it's not easy to recover
individual or sets of files, it's the whole thing. A disk image like Ghost
or Drive Image offers a bit of both. It's faster to recover the boot
partition than backup software, but not as fast as a mirrored disk. It
allows you to recover individual files and make multiple copies easier than
a mirrored disk too. In some cases, like the IBM situation I mentioned
above, it can be faster at getting both drives back to the same state than
a mirror rebuild. For people testing changes to a server like a service
pack update, who can't afford lots of drives, and need multiple backups,
drive images are the way to go.
I would want mirroring. But can I use Win2K to do it?
Yep. You can either use the hardware mirroring feature of a hardware
mirroring controller (if the maker supports Win2K drivers for his product)
or use Win2K's feature. I'll say right now, I don't know if Win2K pro
offers software disk mirroring. I know Win2K server does, but for some
reason I don't think Pro does. Like I said, I personally only have used
hardware mirroring.
I am very partial to Western Digital hard disks. I also hear that IBM
are bullet proof too. I am told by those who make a living doing this
sort of thing that any other disk is crap. That's a bit harsh, but
they swear by WD.
Everyone has their favourite drive I guess. Every vendor has their bad
batches of drives too, and WD is no exception. They've had bad batches of
Caviar ATA drives that were notorious for failure. I think the best way to
go is get the drives which are cheap enough for you to afford extras, but
also get the ones with the best warranty if you can for the same price.
Some vendors offer 3 years for the same price as other vendors 1 year
warranty. If the drive in that case costs the same or less, and you can
get more warranty, and the drive is easy to get, then that's what I would
do.
You find in server drives, the drives that are labled HP or Compaq are
actually from a wide number of suppliers, if you take them out of their
hot-swap chassis.
A lot of people had problems with the IBM 75GXPs, including me. I went
through 3 of them before I switched to something else. But my 22GXPs have
never given me a problem. A lot of people have been complaining about
Maxtors recently. I've got the 40 and two 160s, have had them for years
now, and no issues at all. It's the luck of the draw. Best you can do is
get yourself some insurance, with good backups (whatever the method) and a
drive warranty.
That sounds like too much for a simple home operation.
Yep, too much for me and you. Not too much for some people who are running
an IT business out of their home though. A good friend of mine runs an
email service out of his basement, offering cheap email accounts for small
companies that don't want to do their own email admin and support. He runs
racks of Compaq Proliant servers and SCSI disk arrays and DLT tape backups.
You would be surprised how many people are running server class hardware at
home.
I have thought of that but I can configure an old PC cheaper.
Yep, if you already have the hardware why not use it. The advantage of the
NAS device is it takes little space and has minimal maintenance. So for
people who don't have much space at home and don't like to do PC setup and
maintenance, a cheap ATA NAS is the way to go. But if you want flexibility
to use the device for more than just file serving, then using a cheap PC is
the way to go.
In the old days I would only run SCSI drives on file servers. But
nowadays the WD ATA drives work just fine.
Yep, many people are finding the same. Even in enterprise situations, you
will find that nearline storage arrays of ATA drives are getting more
popular. You can get huge amounts of ATA storage for less than the cost of
comparable tape storage, and it's far faster than tape. You can get a
backup to ATA done far faster, cutting your backup window down to a
fraction of what it was with tape. Then you can backup ATA to tape and
take your time about it. You get two backups instead of just one, and you
get a shorter backup window which is a bonus too, especially for things
that need to be shut down for proper backups like some databases. Instead
of a single database backup per day to tape, you can afford to do one to
the ATA storage every hour. Less downtime for backups, less downtime for
restores.
Everything has a cost associated with it. For some people, they can't
afford down time, it could be their business depends on it, or maybe just
their sanity and frustration level. So rather than risk the chance that
one backup method failed, they will spend money to minimize downtime or do
multiple backups and recovery methods. For others, rebuilding a system
from scratch is no big deal. It might take a day, it might take a week,
it's no sweat to them. As long as the data is on a CDR or DVDR somewhere,
they are happy. And if it turns out the CDR or DVDR is bad, they don't
care, they start again from scratch. If it's the first example, they can't
afford to risk what might happen if an optical disk can't be read, so they
make multiple copies, send some off-site, and regularly try to verify a
restore just to make sure the disk is good before they store it. They test
every backup with a verify.
So if it seems like I'm not answering your questions, its because I try
never to assume what a "home user" needs. Everyone has different ideas of
what they consider acceptable risk.
Personally, my own backup situation is the following: I make Ghost images
of my boot partitions. I have an image with just the base operating systems
installed. I have another with just the base and Microsoft service packs
and updates. I have another with all my apps installed. And I keep one
more that is recent or "up to date" before I make any changes like updating
the video driver. I keep all these on another hard drive in the system,
and I burn copies to DVDRW. In the event I screw up my system because I
installed some crap software or driver, I restore whichever GHOST image I
want to my OS. This works for me, and is cheaper than buying drives to
mirror. But it's only as good as my last disk image. If I install some
apps or drivers to my OS drive, and don't bother to do an image, then I
won't have them if my disk dies. I will have to recover from an older
image, and re-install those apps and drivers. Not a big deal for me. But
not as fast as if I had a mirrored drive, in which case I just pull the bad
drive and boot off the good one.
On the other hand, with a mirrored drive, it's only as good as the mirrored
drive I've pulled. If I install drivers, it goes on to both drives, unless
I pull one first. If I forget to pull a drive, I have no backout. So
before a driver or Windows update, I might pull a drive, just in case,
reboot, and the system comes up and looks OK. I test some apps out, and I
think the driver is fine, so I put the pulled drive back in and let it
rebuild the mirror. Then days later I find my system is flakey or that a
program I didn't bother to test before now does not work after the driver
install or windows update. Whoops. Since I've put the drive back in to
rebuild, I can't use it to go back anymore. I have to figure out how to
resolve the driver or update issue, by uninstalling it or some other
method. Frequently drivers or updates won't uninstall cleanly or at all.
With a disk image or regular backup, I could have kept that copy of the
"old" system around for as long as I needed it, just in case the updates
caused problems. If I had money to burn, I could keep a dozen ATA drives
around, all backups of the boot drive and OS, labled and dated so I could
go back to various backups without the updates, and recover from there. I
actually do this for some servers at work. But most people wouldn't have
the money for this. Just an example of what to be aware of when using
mirrors vs images and backups.
The only thing I might loose of any importance are my Internet Explorer
favourites, which I backup by hand. I should just set a script to copy
them on a scheduled interval.
I backup my Apps partition as well, but I only have one copy of that on
DVDRW. It doesn't change much and I can always re-install apps. I do have
multiple copies of the app install sources on CDR and DVDR. So if one dies
I can get it off another, or off the originals.
Data I back up on DVDR. I probably don't back it up often enough. But the
worst I would loose would be my tax info, which I have on paper. I backup
image scans and digital photos to CDR or DVDR. I keep all my Data on a
separate drive. Anyone using the computer knows to save their data to that
drive only. So I never install apps to that drive, and they never store
data to the apps drives, etc. This reduces the chance of me screwing up
the data with an install, or that someone looses data because they didn't
save it in the right place.
By default, Microsoft sets it up so you save data in your profile. This is
BAD, because that's the location that's going to be wiped out if you do a
disk image or recover from a mirror. So I have to tell every app I use to
store data in a location that is different from the default. This is the
one weakness in my backup strategy. Another way around it would be to use
backup software or a script to backup the profiles every day. This would
reduce the risk of someone losing their data because saved their data to
the profile folder anyways instead of the data drive, and I did a partition
restore wiping out their profile.
The rest of my stuff consists of games, which I have the install disks for
on CDR or DVDR, mp3s, which I have the original CDs for, and AVIs, which
are distributed on the net and I could get again if needed. But I don't
like the prospect of re-ripping all my CDs or re-downloading the AVIs. So
I plan to get another 300GB drive and backup to that. The MP3s are also
backed up on my MP3 player which has 60GB. But I'm going a step further.
I'm going to re-rip all my audio CDs to a lossless format and back that up
to both hard disk and DVDR. It should take about 10 DVDRs to backup my CDs
to lossless FLAC format, which is close to 2-1 compression. The AVIs I'm
going to have two copies of, one on 160GB drive, one on 300GB drive.
Eventually I will burn them to DVDR, most likely in AVI format. Any AVIs
that are important to me I already have on DVDR. I have another PC, P133
running 98, Office 2000, that I can use to get on the net. As long as I
can connect to work, I don't need anything else at home. Any PC with a web
browser and internet connection can get me logged into servers at work
running Citrix / Metaframe. So if my main system died tomorrow, I'd still
be OK. My tolerance for a system failure is quite high. Other's aren't so
lucky.
Thank you and the others for all the helpful info. Unless I change my
mind it sounds like I want disk mirroring with removable drive bays. I
wonder if those hot-swap bays really work. I am using a cold-swap unit
now because I never trusted hot-swap. But if I am going to be removing
mirrors periodically for a network file server then I would want
hot-swap.
I don't have any experience with ATA hot swap but I've recieved many
replies from people who are using it with success. I'd post another thread
with the subject ATA RAID 1 Hot Swap Recommendations and find out what
brand of controller cards and drive bays people are using. I don't know
whats required to ensure there are no problems when you connect a live ATA
bus to a live ATA drive. See if you can find the recommended controllers
and drive bays from your local vendor and make sure they will let you
return it if you find you can't get it working.
You'll want to run through all of the typical drive failure scenarios.
Pull a drive, power off, see if it comes back up. Shut down. Try the
rebuild process, whatever the manual for the controler says. Once you have
the mirror rebuilt, then shut down, pull the other drive, and try to boot
off the freshly mirrored drive. If it works so far, re-mirror the drives.
Try pulling a drive with system on and reboot. Try pulling a drive with
the system off and boot. Etc. Try both drives in both ways. I can think
of at least 4 test runs and rebuilds that I would do.
If the mirrored drive is not your boot drive, then you'll want to do the
same tests, but change or add some files on the mirror just to keep track
of if the drive is actually mirroring or just showing you what was there
already.
