RAID solution with hardware assistance. RAID parity calculations can be performed by either the main CPU, or by a separate processor on the RAID controller card.
47
votes
8answers
3k views
How can a single disk in a hardware SATA RAID-10 array bring the entire array to a screeching halt?
Prelude:
I'm a code-monkey that's increasingly taken on SysAdmin duties for my small company. My code is our product, and increasingly we provide the same app as SaaS.
About 18 months ago I moved ...
20
votes
4answers
986 views
Do raid controllers syncronize HDD platter rotation?
I'm in the market for a new storage solution. While researching various specs one of my coworkers said that some raid controllers can synchronize HDD rotation to the effect of all drives' sector/block ...
16
votes
3answers
4k views
Linux - real-world hardware RAID controller tuning (scsi and cciss)
Most of the Linux systems I manage feature hardware RAID controllers (mostly HP Smart Array). They're all running RHEL or CentOS.
I'm looking for real-world tunables to help optimize performance for ...
11
votes
11answers
2k views
Is RAID5 more robust than RAID1
I am about to replace an old hardware RAID5 array with a Linux software RAID1 array. I was talking to a friend and he claimed that RAID5 was more robust than RAID1.
His claim was that with RAID5, on ...
7
votes
7answers
17k views
What is a (raid-controller-) BBU for?
I am wondering what's the purpose of a BBU. My first understanding was, that it enables the cache to write the data to the disc during a power failure. But some specifications say that a BBU can hold ...
7
votes
8answers
617 views
Recommendations for hardware RAID controllers [closed]
I'm looking for a hardware RAID controller. I want something that:
Can support 8 or maybe 16 hard drives
Won't randomly break, lose my data, etc.
Does anyone have recommendations? It seems like ...
7
votes
3answers
622 views
RAID array Considerations - Any advice?
We just bought a Dell PowerEdge r510 (12 drive bays) that will fill the role of an archive server. We have 6 drives (1TB each) installed.
The plan is to have all the drives in a single RAID array and ...
7
votes
5answers
3k views
Software vs. Hardware RAID1 (Mirror)
How does the Software Mirror in Windows Server systems compare to an affordable hardware/BIOS RAID?
I've had some rather bad experiences with onboard hardware RAID controllers, so I would want to ...
7
votes
3answers
815 views
Do disks in Raid-1 function outside of the raid?
Raid-1 is mirroring two disks (if I haven't messed up completely here :p). Does that mean that I could take one disk out and put it into another machine and it would work like a normal disk? Or does ...
7
votes
2answers
982 views
Can enabling a RAID controller's writeback cache harm overall performance?
I have an 8 drive RAID 10 setup connected to an Adaptec 5805Z, running Centos 5.5 and deadline scheduler.
A basic dd read test shows 400mb/sec, and a basic dd write test shows about the same.
When I ...
6
votes
3answers
467 views
Would unplugging a drive simulate a drive failure?
I just set up a RAID 1 array, 2 2tb drives mirrored.
I am wondering what will happen if one were to fail.
Would unplugging one of them be a valid test?
I am using the Onboard controller of an asus ...
6
votes
1answer
597 views
I have a 21TB array but only 16TB is visible from Windows
CONTROLLER
Raid Controller: 3Ware 9650SE-24M8
Disks: 21 x 1TB RAID5
Stripe 64KB
WINDOWS
OS: Windows Server 2003 SP2 32x
Disk: Dynamic 19557.44GB
Volume: Capacity 15832.19GB
I guess my array ...
6
votes
4answers
8k views
Monitoring hardware RAID on VMWare ESXi
I've got an ESXi 3.5 server on "unsupported" hardware - SuperMicro motherboard, Adaptec 9410 3405 RAID controller (oops, the 9410 is the onboard controller that's not being used for RAID) - and I'm ...
6
votes
2answers
2k views
How long should rebuilding 250GB take?
In a PowerEdge 1900 have I a hardware RAID 5 of 5x250GB disks + 1 hot spare 250GB.
Disk 2 have errors, so I forced it offline in the raid bios to replace it.
Now it have been rebuilding to the hot ...
6
votes
2answers
288 views
Are different RAID cards setups compatible?
I'm setting up a new NAS/SAN system with RAID5, and I was wondering if going the software or hardware RAID way because I had this question in mind:
If my hardware-RAID card fails, will I need to ...
6
votes
1answer
325 views
Areca - expanding a raid by swapping out disks for larger ones
What I am looking to do is, one by one, replace the drives in my current raid array (in a 1680i). After the drives are replaced by their larger counterparts, I want to do an online expand of the ...
5
votes
4answers
5k views
Why do I need a raid battery pack?
I'm trying to understand why one would add a batterypack to a raid card. It seems to me like if power goes down, running just the raid card is going to do little good: without power for HDs and ...
5
votes
5answers
4k views
Poor read performance on Dell Perc H200 RAID10 with (4) 1TB 7200rpm 64MB drives
I am seeing only 50MB/s reads:
ensnare@box:~$ sudo hdparm -tT /dev/sda
[sudo] password for ensnare:
/dev/sda:
Timing cached reads: 4592 MB in 2.00 seconds = 2296.48 MB/sec
Timing buffered disk ...
5
votes
3answers
10k views
HP ACU CLI Examples
Has anyone used the HP Array Configuration Utility Command Line Interface (hpacucli.exe) to get physical disk information into a file?
I'm not at the machine right now, but basically I want to find ...
5
votes
2answers
640 views
Linux: How to align partition and file system on hardware RAID
I have a test box (PowerEdge 2950) with a Perc 6/i and 4x 15.5k SAS drives attached (with 512 byte block sizes). These are in a single RAID 5 virtual disk with a 64KB chunk size.
I am creating a ...
5
votes
2answers
988 views
LSI 9260-8i w/ 6 256gb SSDs - RAID 5, 6, 10, or bad idea overall?
We're provisioning a new production server for our reasonably busy website. Our choice of host have available a 6 drive configuration with a LSI 9260-8i card.
My initial thought was to fill all six ...
5
votes
3answers
963 views
Four disks - RAID 10 or two mirrored pairs?
I have this discussion with developers quite often. The context is an application running in Linux that has a medium amount of disk I/O. The servers are HP ProLiant DL3x0 G6 with four disks of equal ...
5
votes
1answer
88 views
what harm can writeback caching have on a degraded disk array?
At work I administer several machines using (real) hardware raid controllers (with battery backed write caches), and these have the nasty habit of falling back to writethrough behaviour when an array ...
5
votes
4answers
598 views
IBM ServeRAID: how to use email alerts?
I just installed a brand old IBM server with a ServeRAID 4Lx card.
I installed the driver, and the ServeRAID manager software v9.30.
Everyting works as expected.
My problem is:
Yesterday, when ...
5
votes
2answers
690 views
PERC 6/i | ext4 | raid5 | 4 disks - improve write performance
I am running several fileservers using this controller, filesystem and disk setup.
All of them are suffering from poor write performance, once the 256MB BBU Write Cache is full i get really high ...
5
votes
4answers
1k views
Poweredge RAID Monitoring and Debian
What tools do you use to monitor hardware RAID Status on Dell Poweredge 2950 (II and III, perc)? I run Debian. I've used a "debianized" version of dell openmanage in the past. I'm looking for a ...
5
votes
1answer
2k views
How to select the best Stripe Size when configuring a RAID Array
There are various "references" on the Internet that delve into some discussion about what factors to consider when selecting a particular RAID stripe size (4KB to 128KB or more) for an array of disks, ...
4
votes
4answers
1k views
Is it normal for a SAS drive to have a few bad blocks, or should I replace my drive ASAP?
I have a drive—part of a RAID 1 mirror—that has two bad blocks. Adaptec Storage Manger e-mailed me when it detected the blocks. It shows 4 medium errors for that drive, but state is still “optimal”.
...
4
votes
1answer
179 views
Dell 2950 - Can I mix SSD with spindle HDDs?
I have a Dell 2950 with a Perc 5/i controller inside it. I don't want to spark a debate about drive types and which is "better" etc etc. Just simply;
I would like to put in 2x Cheetah 15.5k SAS ...
4
votes
3answers
467 views
Defragment an Exchange Volume
The Scenario:
I use a dedicated volume (RAID volume) to store all of my data for my Exchange 2007 server. Today, out of curiosity, I decided to check up on how fragmented the files on this data ...
4
votes
3answers
37k views
How to check if hardware RAID is configured?
I have several servers running Windows 2008 and Red Hat 5 that are capable of hardware RAID. How do I check that hardware RAID is configured?
4
votes
6answers
1k views
What is the best way to RAID external drives?
I love the fact that you can now buy 1 and 2 TB drives cheap. However that much data on a single drive scares me. What would be the best way to build a raid system out of external drives? I am looking ...
3
votes
5answers
703 views
RAID hard drive configurations
I'm building a linux traffic shaping routing box for a leased line connection. This box has to be reliable, so I'm planning on installing the operating system and data files on a RAID 1 configuration. ...
3
votes
3answers
2k views
What are the good ways to migrate a RAID array to bigger disks?
I'm looking to replace my hard-drives with bigger-ones and I would like to know what are the best practices in doing this.
I have a HP ProLiant with its 256MB version of RAID controller:
03:00.0 RAID ...
3
votes
2answers
229 views
Adaptec 2405 “Knight Rider” LEDs - fault?
I have an Adaptec 2405 installed on ESXi 5.0. When the card is idle, it flashes the red LEDs back and forth, Knight Rider -style, just like this video. Is this normal, or is this a fault? I have dug ...
3
votes
1answer
179 views
Set device offset in Linux due to failed hardware RAID?
I have a failed hardware RAID card. This card had two drives in a RAID-1 mirror. Plugging one of the drives into the motherboard shows no partition table. Using a program like testdisk, I can see ...
3
votes
5answers
904 views
Server with 3 Disk, what's the best HD Configuration?
I Have an HP Server with a quad core Opteron and 3 Disk 250Gb S-ATA Disk, i'm thinking about what's the best configuration of the disk for performance and reliability.
There is mainly 2 scenario :
...
3
votes
4answers
299 views
Can I keep the data on my Raid 1 drives if I move them to a new Raid controller?
I have a couple of servers I'm about to decommission and they each have 2 raid 1 drives. I want to take these drives and put them in a DAS but I am told that I will lose the data because the raid ...
3
votes
3answers
782 views
Why does a RAID-0 volume randomly fail with healthy drives?
I have had a pair of 5 year warranty WD Velociraptors hardware stripped on an intel ICH8R motherboard controller for about 1.5 years.
The other day, the volume randomly failed during no specific ...
3
votes
3answers
4k views
Is this a critical RAID error?
If I do the following
/opt/MegaRAID/MegaCli/MegaCli -LDInfo -Lall -aAll -NoLog > /tmp/tmp
/opt/MegaRAID/MegaCli/MegaCli -LDPDInfo -aAll -NoLog >> /tmp/tmp
then I see these errors
...
3
votes
1answer
616 views
RAID controller question: NVDIMM or not?
I am in the market for a new RAID controller for a Dell server, and I have a choice between "PERC H700 512mb Cache" and "PERC H700 512mb NVDIMM Cache". There is a $200 difference between the 2 cards, ...
3
votes
2answers
433 views
Replacing a Hard Disk in RAID 5 Array with Newer Version
Recently, 1 out 4 disks in my RAID 5 array failed. I searched for a replacement part and learned that only a newer version of the hard disk is available. This "newer" version has the exact same specs ...
3
votes
1answer
403 views
Can I mix SAS and SATA2 drives on one controller?
I've read here that I can't mix SAS and SATA2 drives on the same controller - is that really true? I understand I shouldn't mix on the same channel, but the same card!?
For example, when I plug my ...
3
votes
1answer
175 views
“Transparent” SATA RAID Controllers [closed]
I'm looking for a true hardware SATA RAID controller that can do levels 0, 1, and 5 and is, for a lack of a better term, "transparent" to the OS in that it requires no software drivers whatsoever. ...
3
votes
3answers
2k views
Ubuntu Server Hotswap RAID 1: Hardware or Software?
I'm building new servers for a project I'm working on. They will all run Ubuntu Server x64 (10.04 soon) and require a RAID 1 hotswap configuration (just two drives) to minimize downtime.
I'm not ...
3
votes
2answers
204 views
Write caching in linux
I have read a lot on serverfault and searched on google about write caching, but still cant find the answer.
I have an HP ProLiant DL380 G5 with HW raid with 512 MB Battery backed cache. I use debian ...
3
votes
2answers
1k views
Monitor LSI 3ware raid controller on ESXi
This concerns a server that runs ESXi (v. 4.x or 5.x) installed on drives that are configured into a raid10 using an LSI 3ware 97050 raid controller.
I would like to know if there is a way to monitor ...
3
votes
2answers
1k views
Replace faulty Dell PERC 5/i controller without losing data
Is it possible to replace a 5/i controller without losing the data on the array? Can I import this as a foreign configuration? Any "gotchas" or tips to make this smoother?
3
votes
1answer
805 views
Remove 1 Disk From 4 Disk RAID 5 Array
Im using a PERC 3/DC controller to run a RAID 5 array using 4 hard disks.
I am hoping to change this to 3 disks in the array and 1 hot spare.
Is it possible to remove 1 disk from the array, ...
3
votes
1answer
241 views
moving raid 10 to another identical server both on Smart Array 6i controllers
I have dead HP DL 380G4 with RAID 1+0 with 1 logical volume from 4x72GB drives on built-in Smart Array 6i 128Mb BBWC. It was shut down properly. It seems it was usual death for Proliant with ILO led ...
