We have a client that has a mail server with two drives. One hard disk is devoted for OS/Application (C and one is devoted for mail storage only (D
The goal is to make the D: drive which is a SATA 320GB drive to be made into a mirror, i.e. add another drive and a RAID Card and make D has a RAID Mirror drive.
My understanding is that when a RAID is configured for drives, the drive will lose whatever data it has on it ? Is there no other way to construct a singular environment into a RAID mirror environment (by adding a drive and Card) without losing drive on one of the primary drives?
I am in a somewhat complicated situation... I wanted to order a custom server with hardware 3Ware RAID controller but after over a month of waiting I was told the HW RAID controller, as well as any other 3Ware controller they tried, does not work with the motherboard used in the server from Fujitsu-Siemens and that they simply got a reply from FS that the controller is not certified to work with their motherboard.
So although I'd prefer a HW raid, I am forced to either choose a different webhost or setup a software RAID. The problem is, I haven't done that before and am somewhat moderately...scared
I have read a lot of the info about SW RAID on Linux that I could find through Google but there are some questions unanswered still. So I thought that perhaps some of the more knowledgeable WHT members could help me with this problem...
The server specs will be:
Core2Duo E6600 (2.4Ghz), 2GB RAM, 6-8x* 250GB SATA II HDDs, CentOS 4.4 or SuSe, DirectAdmin
* I prefer 8 HDDs (or actually 9) over 6 but I am not sure if their server chassis can hold that many HDDs, I am awaiting answer from them. They don't have any other drives beside the 250GB ones so I am limited to those.
The preferred SW RAID setup is to have everything in RAID 10, except for the /boot partition which has to be on RAID-1 or no RAID I believe, plus one drive as hot spare (that would be the 9th drive). I am quite sure they will not do the setup for me but will give me access to KVM over IP and a Linux image preinstalled on the first HDD so that I'll have a functional system that needs to be upgraded to RAID-10.
How do I do that? The big problem I see is that LILO or GRUB can't boot from a software RAID-5/10 so I will have to mount the /boot partition elsewhere. It's probably terribly simple...if you have done it before which I have not. I have read some articles on how to setup a RAID-5/10 with mdadm (e.g. [url] ) but they usually do not talk about how to setup the boot partition. Should it be setup as a small sized (100-200MB) RAID-1 partition spread over all of the drives in the otherwise RAID-10 array?
What about swap? Should I create a 4-8GB (I plan to upgrade the server RAM to 4GB in near future) RAID-1 swap partition on each of the disks or swap to a file on the main RAID-10 partitions. The second sounds simpler but what about performance? Is swapping to a file on RAID-10 array a bad idea, performance wise?
Is it possible to grow a RAID-10 array in a way similar to growing a RAID-5 array with mdadm (using two extra drives instead of one of course)? mdadm doesn't actually even mention RAID-10 despite it does support it without having to create RAID-0 on top of RAID-1 pairs if the support is in kernel, from what I know.
I have 2x250gb drives, and this is my output of fdisk -l:
Quote:
Disk /dev/hda: 250.0 GB, 250059350016 bytes 255 heads, 63 sectors/track, 30401 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System /dev/hda1 * 1 13 104391 83 Linux /dev/hda2 14 30401 244091610 8e Linux LVM
Disk /dev/sda: 250.0 GB, 250059350016 bytes 255 heads, 63 sectors/track, 30401 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes
Device Boot Start End Blocks Id System /dev/sda1 * 1 30401 244196001 8e Linux LVM
I see the LVM is some sort of manager and it looks like the 2 drives are indeed set up as LVM, but I can't really tell what the means or how they are set up.
I'm looking to have them in a RAID-1 setup - a copy across drives so that it will continue working even if a drive fails.
we've got our new machine up and running smoothly. It's a core2duo running CentOS with Plesk 8.3. We have 2 drives in a RAID 1 configuration for reliability sake, and I'm looking for something to help me monitor the status of the disks in the array. Since RAID is pretty useless unless you know if one of the disks has died.
Is there some open source utility that will monitor this and email me if something is wrong? Perhaps something with a nice web interface?
Even better... is there some addon to plesk that will help with this?
I have a question regarding, hard drives and performance etc... I only use it for forums and currently is only one site (hopefully couple more in no time)
Currently I have 2x36gb SAS in raid 1 obviously containing everything including dbs and /home. and a third 250gb drive for backups only ^^ Ronny did an excelent job setting this up.
Any ways, my problem is that I wan't to allow some attachments on my forums, and this would take a significant ammount of space over 1gb no problem and then keep increasing (that's gonna sux for bandwidth). I know it will fit in the SAS drives no problems, dbs are rather small at the time (2.5gb in total) but logs are quite big 5-10gbs in total.
I thought it might be a good idea to purchase another drive. This 4th drive would be 750 and backups would move there , and use the 250 for the /home directory. This would give a lot of room for uploads, and backups accordingly and keep the fast ones for OS and dbs
I was told, however, and understandebly, that a lot of performance would be lost by moving /home to a SATA drive I know SATAS are no way as fast, but then vbulletin can't upload attach files to a folder outside its hirachy (without complicated modifications). (Note: i didn't specify my resons for wanting such set up)
So I'm in a bit of a pickle. Having the bigger drive would allow me to have the attachments, and should eventually result on more traffic etc to my site. /home currently is only 150mbs big... but then performance is also an issue pitty i couldn't afford the bigger drices at the time [sees the point of renting over buydowns now]
is there a way that /var/log/httpd saves those massive logs on another drive? it would free up 5-10gbs
in shortIs moving /home to a SATA drive from Raid 1 SAS a bad idea? (considering space and purpose)
Could httpd logs or /var/log in general be moved to the backup/another drive?
I have a Red Hat 8 server with RAID 1 setup and now I need more HD space.
I managed to replace both 40 gb disks on the raid array with 200 gb disks and the system stayed perfectly alive, BUT I still have only 40 gb of space available (and 160 gb of space somewhere hiding).
Is there a method on Red Hat 8 to get the rest of the disk in use?
At first I replaced another 40 gb disk with a new (empty) 200 gb disk and then on the raid setup I mirrored the old disk with the new disk. After that I replaced that another old 40 gb disk with a new 200 gb disk and did the mirroring again. Got both new 200 gb disks working on the RAID 1 array, except that little problem with space available on Red Hat 8..
Not sure if this is too specific for this forum or not, but since I've gotten great advice here in the past I'll give it a shot.
I have a colo'd production server with a 3ware 9500S-12 RAID card and 12 400GB drives attached. The drives form 3 arrays:
1) 2 drive RAID 1 (400GB)
2) 2 drive RAID 1 (400GB)
3) 6 drive RAID 5 (2TB)
plus 2 global hot spares.
For a variety of reasons I need to change this setup so that array 1) and 2) remain as is, and array 3) is removed and those 6 drives replaced with 6 new 750GB drives in JBOD mode. I've copied all the data from the RAID5 array number 3) onto 3 of the new 750 drives (the 2TB array wasn't completely full,) and I have 3 other blank 750GB drives.
What's the best / safest way to do this? Ideally I'd like to remove the 6 old 400GB drives and retain the ability to plug them all back in and get my old array back (if something goes horribly wrong doing the switch.)
Do I need to reboot into 3BM (3ware Bios Manager) to do this, or can I do it from the command line?
Is there any problem with having a drive that already contains data written to it by another system, and bringing it up on the 3ware card in JBOD mode with the data intact? (All filesystems are ext3.) I'm not going to have to reformat the drive, am I?
Is there any problem with the new drives being SATAII (Seagate Barracuda ES 750GB) but the old drives (and I think the 3ware card, and certainly my motherboard) being SATAI? I've read that this should "just work" but of course I am nervous! There are no jumpers I can see on the 750GB drives.
Will it be possible to remove the RAID 5 in such a way that I could plug the drives back in and get the array back?
I am currently in the process of upgrading my web/mysql server due to heavy loads and io waits and have some questions. I am trying to be cost efficient but at the same time do not want to purchase something that will be either inadequate or difficult to upgrade in the future. I hope you can provide me with some guidance.
This server is a Centos Linux box, running both apache and mysql. The current usage on the box is:
Mysql Stats:
50 mysql queries per second With a ratio of read to write of 2:1 Reads are about 65 MB per hour and writes are around 32 MB per hour.
Apache stats:
35 requests per sec
The two issues that I am unsure of are:
- Whether or not i should go with Raid-1 or Raid-5
- Whether or not I should use Sata Raptor drives or SAS drives.
In either configuration I will use a dedicated Raid controller. If I went with SATA, it would be a 3ware 9650SE-4LPML card. If I went with SAS, I was looking at the Adaptec 3405 controller.
Originally, I was going to use 3 x 74GB Seagate Cheetah 15.4K SAS drives in a Raid-5 config. After more reading, I learned that raid-5 has a high write overhead. Though read is definitely more important based on my stats, I don't want to lose performance in my writes either. With this in mind, I looked into doing Raid-1 instead.
I came up with these choices:
- Raid-1 - 2 x Seagate ST373455SS Seagate Cheetah 15K.5 SAS. HDs & controller costs are $940.
- Raid-1 - 2 x WD Raptor 74GB 10K SATA 150. HDs & controller costs are $652.
- Raid-5 - 3 x Seagate Cheetah 15K.4 ST336754SS 36.7GB. HDs & controller costs are $869.
- Raid-5 - 3 x WD Raptor 36GB 10K SATA 150. HDs & controller costs are $631.
As you can see we are not looking at huge differences in price, so I would be up for any of these options if I could just determine which would give me the best performance. I also know that I should have a 4th hotspare drive, but will buy that later down the road to ease cash flow in the beginning. If I went the SATA route, I would buy the 4th immediately.
From what I can tell, both configs provide the same redundancy, but are there any major performance considerations I should take? From what I have read, scsi/sas can enable database applications to perform better do to a lot of small and random reads and writes?
I recently build a server with Asus M2N-MX SE motherboard and SuperMicro 14" mini 1u. On the back of the Asus M2N-MX SE manual. it said for RAID driver, i need to create it from the included CD and use a floppy disk. my question is how can i do it without a floppy disk? i have an external DVD-burner that i hook up to usb to install the OS. Is it possible to use a cd to install the driver when i press f6 during Windows2003 installation?
Is it worth the effort to setup RAID 1? I have two Maxtor 500GB SATA disks and using RAID 1 seem to reduce one disk and leave me with 500GB worth of space and is the onboard Nvidia RAID trust worthy? because it said due to chipset limitation, the SATA ports supported by the Nvidia chipset doesn't support Serial Optical disk drives (Serial ODD).
I've taken the scalable approach when it comes to servers for my various sites. With shared servers, I never really worried about backup or even hard drives going down. Same goes for VPS. For some reason, when I moved to dedicated servers, I outfitted them with 74GB SATA drives in a RAID setup. My understanding is that it protects me if one drive happens to fail. I've been lucky and haven't had that problem.
I'm at the point now where I'm looking to upgrade from a VPS paying around $75 per month to a dedicated server. I can stand to be down a day if a hard drive goes, if it means $75 a month in savings. My biggest concern would be suggestions on the best way to protect myself in the event of a catastrophe.
Contacted SoftLayer about possibly adding a second server for me and honoring the price I'm paying on my old server.
Finally, both the old and new site are seeing roughly 3,000 visits per day. The server I'm considering is a Clovertown 5320 1.86 dual quadcore, 4GB RAM, RAID, 2 74GB Cheetah drives,100mbps, 2000GB bandwidth. Is this overkill or the right server for the job?
Today we are going to conduct a detailed study of RAIDability of contemporary 400GB hard drives on a new level. We will take two "professional" drives from Seagate and Western Digital and four ordinary "desktop" drives for our investigation. The detailed performance analysis and some useful hints on building RAID arrays are in our new detailed article.
Is Motherboard RAID as good as a dedicated PCI-E card? I am guessing a dedicated card is the best option, though costs more.
We are looking at buying a barebones server from Supermicro. It features an onboard RAID controller which supports RAID 0, 1, 5 & 10 - but for some strange reason it will only support RAID 5 if you use Windows. Here is a link to the page detailing the RAID features.
[url]
We are going to be running Linux, CentOS 5.1, so we will only have the choice of RAID 0, 1 or 10. This isn't an issue, as having RAID 10 on 4x SAS (15k) drives will be fine for speed and stability. What is an issue is would this RAID controller be as fast or reliable compared to a dedicated PCI-E card? If it can only use RAID 5 in windows, does that suggest this controller is too reliant on software? It would be a nightmare to suffer downtime and data loss because the controller couldn't hack it during a drive failure, or one day it decided to bugger up the array when rebooting.
So that leads me to looking at this card, this looks very good for what we need. Are adaptec a reliable brand? I've seen it advertised for £200, which is a good price.
[url]
This card features RAID 5 and 6, would RAID 6 be better than RAID 10 for redundancy, or is it too slow to bother with? Also it seems to have a battery module available for it, what does this achieve? Cos surely if the power dies the hard drives and motherboard can't run off this little battery, or does it just help the controller stay alive long enough with some hard drive information in its memory if the power goes out during a rebuild?
How often do RAID arrays break? Is it worth having RAID if a servers hard drive goes down? I was thinking it may just be a better option to just have a backup drive mounted to my system and in the even of a system failure just pop in a new hard drive, reload the OS, and then reload all my backups?
I am in the process of restructuring the infrastructure on our servers. I am thinking of using either RAID 5 (1 hot spare) vs RAID 10 as my 1U server has 4 HDD tray.
RAID 5 would have better capacity but RAID 10 has better overall performance. Which one do you guys go for a shared hosting server?
Is it possible to turn a non raided setup into Linux software raid, while it is live, and if it's the OS drive? Can you even software raid the OS drive remotely? I've been thinking about doing it for the redundancy (and possible slight performance boost for reads, but doing it more for redundancy). I'm using CentOS.
I've been talking to the Planet about trading in my four and a half year old "SuperCeleron" (from the old ServerMatrix days) Celeron 2.4 GHz system for something new. As part of their current promotions, I've configured a system that looks decent:
Xeon 3040, 1 gig of RAM, 2x250GB hard disks, RHEL 5, cPanel+Fantastico, and 10 ips for $162.
Not too bad. I could bump up the ram to 2 gb for, I think, $12 more, which I'm thinking about and wouldn't mind some thoughts on. But, the thing that has me really confused is RAID. I like the idea of doing a RAID 1 setup with those two hard disks. But, the Planet wants $40/month for a RAID controller to do it. I really don't want to go over $200 a month!
Any thoughts on alternative redundancy strategies that might avoid that cost? Software RAID does not seem to be offered by the Planet, unless I can figure out how to do it after installation (is that possible?) Better ideas in general on the server?
Are there any significant difference between 4 15K SAS HD in RAID 10 versus 8 7.2K SATAII HD in RAID 10? I have the same question for 2 15K SAS HD in RAID 1 versus 4 7.2K SATAII HD in RAID 10.
I have room for 4 more hard drives on my home server. My original goal was to go raid 10 but I've been thinking, raid 5 can support 4 drives and give more capacity. Which one would have better performance as software (md) raid? I'm thinking raid 10 might actually have bad performance as software raid, vs hardware, compared to raid 5. Would raid 5 with 4 drives be better for my case?
We are looking to build our first server, and collocate it. It will be a higher investment than just renting the server, but will be worth it in the long term, and we have already decided we are going to support the hosting business for a minimum of 3 years - so we might as well invest in a server from the outset to benefit from lower data center charges and higher redundancy and performance.
We are currently looking at Supermicro for servers as they offer 1U barebones systems with dual hotswappable psus and upto 4 hotswappable drives. This would be ideal for redundancy, and also for taking advantage of the speed and redundancy that a RAID 10 array would give you. These two factors combined are very appealing as it would reduce the possibilities of downtime and data loss. Obviously we will be backing up daily, but its good for piece of mind to know that you could potentially blow a PSU and 2 hard drives, and your server will still be up long enough for a data centre technician to replace the parts.
Now then, my business partner and I are currently deciding what the best all round hard drive configuration would be. He has decided that we should opt for SAS instead of SATA to have lower latency seek times, which would give us better performance. I agree, though this does increase costs considerably.
He is then arguing that we use RAID 5 on cost grounds. He says we should only use 3 of the slots to begin with, save money on one drive by not having a spare, and hope we don't have a drive failure - which sods law will happen. I'm not happy us cutting corners to save money, because if we gamble and lose, that's a hell of a mess we have ourselves in, and will cost us a load more time, reputation and data center charges to get ourselves out of it.
I say we might as well go for RAID 10 for that extra performance, and redundancy, you can potentially lose 2 drives so long as they aren't from the same mirrored pair. With RAID 5 you can only lose a drive, it takes longer to rebuild onto a spare, and during rebuild the performance takes a hit. Also RAID 10 is much faster than RAID 5, and at the expense of the cost of a drive.
Now the question we should be asking is... would a SATA2 RAID 10 array provide better performance than a SAS RAID 5 array?
So I think the choice we have to make is either go for RAID 5 and run with a hot spare, and stock a cold spare, or go with RAID 10 and stock 2 cold spares.
We are considering going with Seagate drives because they are high performance and have 5 year warranties. I have had to RMA two Western Digital drives already in the past 12 months, a raptor and a mybook, both deaths invoked data loss.
The server is going to be a linux web, email, dns and mysql box. It will likely feature a single dual/quad core processor, and 4-8GB of unbuffered ddr2 ram.
