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Dan Goodinson
2004-12-10, 07:59
The point still stands though - there are 2 _completely_ different
techniques being discussed in this thread.

1. RAID
2. Backups

They are different. They are not the same.

RAID is only about protection from hardware failure. It's not backup.
The "R" in "RAID" means "redundancy". Protection from hardware failure
in the event that a disk fails. It is absolutely NOT backup!! A couple
of people mentioned that if the system becomes corrupt or gets attacked
by a virus, or gets some malware lodged in there than RAID will
duplicate that too. RAID will "backup" the virus also.

Of course it will! That's because it's NOT a backup! It's just a
"spare" disk in case you have hardware failure. If you are only using
RAID then you have no backup - it's as simple as that. All you have is
some protection against a disk failure.

There are different levels of RAID, but I'm talking mainly about those
involving mirroring. An earlier thread talked about "everything being
lost is a single sector on any disk fails". Yes - that's RAID 0. It's
for performance only - there is no redundancy (it should be called "AID
0"!). In real terms, RAID 0 is worse than a system WITHOUT it, as you
are effectively introducing more points of failure. If you have 1 disk
without RAID 0, then you only have the chance of 1 disk failing. If you
have 2 disks with RAID 0, then you now have to contend with one of the 2
disks failing... If you want to use RAID 0, you're probably best off
getting RAID 10 or RAID 01 - unless the thought of losing your system is
not that much of a worry...

But for the record though - RAID is NOT a backup. "Don't go for RAID as
a backup" - because it isn't a backup tool. It's like saying "don't buy
a frying pan to mow your lawn".

-----Original Message-----
From: discuss-bounces (AT) lists (DOT) slimdevices.com
[mailto:discuss-bounces (AT) lists (DOT) slimdevices.com] On Behalf Of Virr
Sent: 10 December 2004 10:11
To: Slim Devices Discussion
Subject: [slim] Don't go for RAID



On Dec 10, 2004, at 0:31, Ralph Edington wrote:

> I love this thread. I gotta jump in here.

I have got to agree. I've actually really enjoyed this thread, and
will add another two cents.

I think the first key is to do backups at all. If you use tape, DVD,
external HDs, a server, whatever. Just backup. Then make it as easy
as possible, or you wont do it often enough. Finally worry about
making sure your backups are stored offsite. If you wait until you can
store backups offsite before doing backups...

I have done backups various ways. From making a print out, to storing
a file on multiple floppies, to backing up to zip disks, to putting it
on an external HD, to CD-R, to DVD-R, to rsync onto a linux server. So
far the last is by far better for me (especially with a laptop). If it
is on the net I don't have to have DVDs, I don't have to wait for a
full copy of 14G, I don't have to worry about running out of space
(yet). It's fast, all I need is one script to run in the terminal, and
I can backup from work or anywhere with highspeed internet access
(nearly everywhere I might create data on my laptop). Granted when I'm
home everything is in one place. I lose one drive, I lose all my
backups. Eventually I'll run out of space with all the incremental
backups. So it isn't perfect, but these problems are all more or less
fixable. The point is to start with backups. Then Make it easy.
Finally make it offsite.

Gotta start somewhere.

Darren

John L Fjellstad
2004-12-10, 10:11
On Fri, Dec 10, 2004 at 04:18:46PM -0000, Kevin Walsh wrote:

> 3. Software RAID is rubbish. It uses far too much CPU and creates a
> lot of drama when you need to replace drives; The drives might
> hot-swap, but will probably not rebuild until you've jumped through
> a load of hoops. Having said that, software RAID can offer some
> failure protection for non-critical systems, so I tend to use it
> as a "better than nothing" option.

I don't know about Windows RAID, but Linux RAID is a pretty good code.
I don't notice the CPU at all (then again, I have dual CPU, so...). And a
couple of weeks ago, one of my disks failed (sitting in a RAID1). All I
had to do was take out the broken one, put in a new disk, tell the
system that I added a new disk, and it automatically started mirroring
the content.

Couldn't be easier.

Sure, I don't have hotswap, but then again, this is a homeserver. I
don't need it (don't mind running in a reduced capacity for awhile).
Just don't want my server to be down while I take my time
getting a replacement disk.

--
John L. Fjellstad
web: http://www.fjellstad.org/ Quis custodiet ipsos custodes

Daryle A. Tilroe
2004-12-10, 12:17
I think everyone is violently agreeing here! ;-) I too
am an IT guy and manage several servers, all with RAID
(at least on the system volumes) and monthly full backups
and nightly differentials and weekly offsite rotation
etc.... In my 10 years experience I have had occasion
to appreciate both RAID and proper backups. However do not
underestimate the time to recover from a system/OS drive
failure. It can take days to recover from a 'simple' HDD
failure; even at home. Personally I would go RAID 1 (or
some sort of nightly data syncing to another HDD) and
backups (ideally offsite once in a while).

Right now at home my system volume and non AV data (eg more
crucial financial data and irreplaceable photos) resides
on a 80 GB RAID 1 array. This is backed up periodically to
an external 60GB HDD that is usually disconnected and stored
hidden. My only risk exposure here is the house burning
to the ground. At some point I will may get another
external HDD and rotate it off site, although this has
privacy concerns. I will actually probably just fire
proof my hiding place. As for my 200 GB of FLACs: well
one copy is spinning and it is synced to another 200GB
internal HDD every night. For disaster recovery I still
have 75% of the original CDs in storage. At some point
I will probably invest in an HD DVD writer and or another
200 GB external HDD drive for offline backups.

As an aside with the low price of HDDs I would not go
RAID 5 unless the data requirements were 1TB+ and you
have a very high end RAID card. RAID 1(+0) has much better
performance when degraded, ie. no performance hit. Also
in a system where the data is usually being read rather than
written RAID 1, properly implemented, has significant read
speed improvements.

--
Daryle A. Tilroe

stephen van vuuren
2004-12-10, 12:42
> 3. Software RAID is rubbish. It uses far too much CPU and creates a
> lot of drama when you need to replace drives; The drives might
> hot-swap, but will probably not rebuild until you've jumped through
> a load of hoops. Having said that, software RAID can offer some
> failure protection for non-critical systems, so I tend to use it
> as a "better than nothing" option.

I worked in the IT field for 20 years and this global statement is
simply not true. Some software RAID is rubbish, some is not. I'm
running the hack for RAID 5 on Windows XP for a video/film/music
production workstation. During DV capture, system CPU usage is 2-4%
and video capture app is 15% - no different from hardware RAID 0
numbers I had before.

It will hotswap if you use SATA hot-swap bays and no hoops for rebuild
(though on my 1 TB RAID 5) a rebuild takes about 8 hours - but then
again RAID 5 rebuild on 35 GB Arrays on Dell Poweredge servers can
take the same amount of drive.

> 4. Beware of motherboard on-board RAID as it's often no better than
> software RAID in its CPU usage and other features. A RAID card
> will probably be a lot better and will be easier to replace.

Again, simply not true globaly. Motherboard RAID varies widely and
plenty of low-cost RAID cards use software only for RAID 5.

--
peace,

stephen van vuuren
www.sharkpc.com

stephen van vuuren
2004-12-10, 12:52
> on a 80 GB RAID 1 array. This is backed up periodically to
> an external 60GB HDD that is usually disconnected and stored
> hidden. My only risk exposure here is the house burning
> to the ground. At some point I will may get another
> external HDD and rotate it off site, although this has
> privacy concerns.

I don't use external HDD for off-site backups, only internal backups.
I still use tape (VXA-2) for several reasons:

(1) HDD are very prone to failure with rough handleing, drops
temperature. VXA tapes can be abused incredibly and still function.
Thus, you really need two duplicate off-site drives to sleep well and
then if both are damaged, you are still without backup.
(2) Cheaper - I shopped around and got 1 TB of backup, including drive
and tapes for $900. That's less than a 1$ a GB and when you factor
external enclosures into the price of HDD drives, they are over $1 a
GB. Plus, you really need double copies to get decent reliability with
HDD as opposed to tape, which double your prices.
(3) Smaller. Easy to pocket, easy take off-site = easy rotation.

Tape is still much slower, but that's what nightly backups are for.

My complete data protection strategy involves:

(1) Nightly drive images (monthly full, nightly incremental via Ghost
9) of all workstaions
(2) Complete anti-virus, anti-spyware and firewall protection
(3) RAID 1 or 5 on large data drives where restores would take long time
(4) Full nightly backups of all important data with off-site rotation

--
peace,

stephen van vuuren
www.sharkpc.com

John Harding
2004-12-10, 14:46
What hack did you find for doing software RAID 5 on Windows XP? I spent
quite a while looking for one when setting up my home server a year ago, but
couldn't find anything...

-John
----- Original Message -----
From: "stephen van vuuren" <sevensmilingsharks (AT) gmail (DOT) com>
To: "Slim Devices Discussion" <discuss (AT) lists (DOT) slimdevices.com>
Sent: Friday, December 10, 2004 11:42 AM
Subject: [slim] Don't go for RAID


>> 3. Software RAID is rubbish. It uses far too much CPU and creates a
>> lot of drama when you need to replace drives; The drives might
>> hot-swap, but will probably not rebuild until you've jumped through
>> a load of hoops. Having said that, software RAID can offer some
>> failure protection for non-critical systems, so I tend to use it
>> as a "better than nothing" option.
>
> I worked in the IT field for 20 years and this global statement is
> simply not true. Some software RAID is rubbish, some is not. I'm
> running the hack for RAID 5 on Windows XP for a video/film/music
> production workstation. During DV capture, system CPU usage is 2-4%
> and video capture app is 15% - no different from hardware RAID 0
> numbers I had before.
>
> It will hotswap if you use SATA hot-swap bays and no hoops for rebuild
> (though on my 1 TB RAID 5) a rebuild takes about 8 hours - but then
> again RAID 5 rebuild on 35 GB Arrays on Dell Poweredge servers can
> take the same amount of drive.
>
>> 4. Beware of motherboard on-board RAID as it's often no better than
>> software RAID in its CPU usage and other features. A RAID card
>> will probably be a lot better and will be easier to replace.
>
> Again, simply not true globaly. Motherboard RAID varies widely and
> plenty of low-cost RAID cards use software only for RAID 5.
>
> --
> peace,
>
> stephen van vuuren
> www.sharkpc.com
>

stephen van vuuren
2004-12-11, 11:42
http://www.tomshardware.com/storage/20041119/index.html

http://members.home.nl/rvandesanden/raid3.html


On Fri, 10 Dec 2004 13:46:20 -0800, John Harding
<john_squeezebox (AT) john (DOT) harding.name> wrote:
> What hack did you find for doing software RAID 5 on Windows XP? I spent
> quite a while looking for one when setting up my home server a year ago, but
> couldn't find anything...
>
> -John
>
>
> ----- Original Message -----
> From: "stephen van vuuren" <sevensmilingsharks (AT) gmail (DOT) com>
> To: "Slim Devices Discussion" <discuss (AT) lists (DOT) slimdevices.com>
> Sent: Friday, December 10, 2004 11:42 AM
> Subject: [slim] Don't go for RAID
>
> >> 3. Software RAID is rubbish. It uses far too much CPU and creates a
> >> lot of drama when you need to replace drives; The drives might
> >> hot-swap, but will probably not rebuild until you've jumped through
> >> a load of hoops. Having said that, software RAID can offer some
> >> failure protection for non-critical systems, so I tend to use it
> >> as a "better than nothing" option.
> >
> > I worked in the IT field for 20 years and this global statement is
> > simply not true. Some software RAID is rubbish, some is not. I'm
> > running the hack for RAID 5 on Windows XP for a video/film/music
> > production workstation. During DV capture, system CPU usage is 2-4%
> > and video capture app is 15% - no different from hardware RAID 0
> > numbers I had before.
> >
> > It will hotswap if you use SATA hot-swap bays and no hoops for rebuild
> > (though on my 1 TB RAID 5) a rebuild takes about 8 hours - but then
> > again RAID 5 rebuild on 35 GB Arrays on Dell Poweredge servers can
> > take the same amount of drive.
> >
> >> 4. Beware of motherboard on-board RAID as it's often no better than
> >> software RAID in its CPU usage and other features. A RAID card
> >> will probably be a lot better and will be easier to replace.
> >
> > Again, simply not true globaly. Motherboard RAID varies widely and
> > plenty of low-cost RAID cards use software only for RAID 5.
> >
> > --
> > peace,
> >
> > stephen van vuuren
> > www.sharkpc.com
> >