|
|
Post by Yojimbo on Apr 25, 2012 19:15:51 GMT
I am planning to reformat my PC and change the RAID setup on it. I am wondering what all will have the smallest performance hit.
Configuration #1 (Current planned configuration) RAID 1+0 or 0+1 I forget which is supported
Configuration #2 (Current setup) RAID 5
Configuration #3 2x RAID 1
Configuration #4 Main Drive solo non RAID remaing Drives RAID 5
Configuration #5 RAID 0
The drives a 4x 500GB 7200 RPM SATA drives and I am using an on board RAID controller.
|
|
|
|
Post by gandoron on Apr 25, 2012 19:23:07 GMT
Stripping - R0 will give you the best performance, but no redundancy.
Mirroring - R1 will give you good redundancy with, close to zero performance implications
So if you are talking about performance + redundancy for a main drive, I would say 0+1 or 10 as some people call it. The performance should be almost the same as R0. However you are talking about 2x the drives, or 50% total space.
Also, repairing a R0 as a main drive is troublesome. Raid 5 is not the best performance.
I personally use a single fast drive (used to be raptor, now SSD) as a primary, then periodically have this copied, backed up to my Raid5 storage (I use a NAS, but could be internal).
-G
|
|
|
|
Post by digs on Apr 25, 2012 19:29:39 GMT
For the best performance you should run them in RAID 0. The only scary thing about RAID 0 is if one of the drives fails you could end up losing all your data since your data is being split amongst both drives. I've been running RAID 0 on 2 WD Caviar Blue's for over 2 years without a problem. I just have to make sure to back up my critical files to another HD every so often.
|
|
|
|
Post by Yojimbo on Apr 25, 2012 19:33:14 GMT
I would prefer redundancy so really the RAID0 is the last option basically if performance is still taking a noticable hit after any of the others. I am mostly wondering what kinda of performance hit the RAID 1+0/0+1, which ever mine supports, will have. I already backed up all my data to a 160GB drive so I don't need the full 2TB or even the 1.5TB of the RAID 5 so a 1TB configuration would work just fine.
|
|
|
|
Post by digs on Apr 25, 2012 19:57:27 GMT
If you go with redundancy you're going to lose quite a bit of performance. See this: www.tomshardware.com/charts/hdd-raid-matrix-charts/Throughput-Read-Average,218.html If I were you, I would either set all 4 up in RAID 0 for maximum performance or set up two RAID 0 configs (2 drives each), one for your OS + Programs and the other for your data files, etc. I would back up my critical files to a separate storage device like an external HD of some sort. You could also set up 2 drives in RAID 0, and then have the other 2 drives not in any RAID config - 1 for your data files, and 1 just for backing up your data. |
|
|
|
Post by gandoron on Apr 25, 2012 20:04:32 GMT
Digs, that link shows Raid 0 and Raid 0+1 as having the exact same performance (RAID 0+1, obviously takes 2x the number of drives).
Also keep in mind that your failure rate of a stipped (0) array (like an 8 drive Raid 0) increases linearly with the number of drives... Which is why additional RAID 1 is so great...but expensive.
-G
|
|
|
|
Post by Yojimbo on Apr 25, 2012 20:06:57 GMT
The drive investment is already there so it looks like im sticking with Configuration #1  |
|
|
|
Post by digs on Apr 25, 2012 20:50:52 GMT
Just keep in mind you're losing half your space & getting 1/2 the read-rate you could in RAID 0.
|
|
|
|
Post by arek on Apr 25, 2012 22:53:49 GMT
TBH, if the drives have decent speed, you should be fine with either of Raid 0 or Raid 10 (or 1+0, 0+1, or whatever you wanna call it). Performance from either should be better than in Raid 5, and with Raid 10 , if something does go wrong you'll have the reduncancy you want.
--Arek
|
|
|
|
Post by Acaos on Apr 26, 2012 2:02:09 GMT
I personally use a non-RAIDed SSD as a system/program drive, and then use RAID5/RAID6ed cheap drives for bulk storage.
HG itself runs on a pair of RAID1'd enterprise SAS drives (backed up off-site). With a good RAID1 implementation and the proper workload, you are not actually losing any read rate (because the drives can be reading different data simultaneously). Obviously your write rate and available space are halved.
One thing to realize is that RAID offers availability, not durability. It can protect you from a single drive going bad, but if your filesystem corrupts or your computer catches fire, your data is gone. So RAID is never a substitute for a backup.
Acaos
|
|
|
|
Post by Yojimbo on Apr 26, 2012 12:46:14 GMT
Im familiar with RAID except performance differences out side of 0 being a boost 1 being slight impact and 5 being a larger impact. I mostly wasn't sure about 10 and various RAID configurations permit various number of drive failures before total RAID failure.
|
|
|
|
Post by mdf on Apr 26, 2012 17:50:24 GMT
I use configuration similar to what Acaos recommended for my personal PC.
Boot SSD, 4-5 drives in RAID
For Read + Write performance + redundancy I'd go with RAID 10.
If you can live with the slower writes, 3-4 disk RAID 5 with 1 available as a hot spare.
I also have a hand-built ZFS based storage appliance (* Nexenta) that I use for critical data, redundant backups, NWN server VMs and database. It supports SSD caching for reads and writes, in-line deduplication, compression, self-healing...etc. So even with RAID, you always want to have a 2nd or even 3rd place to back-up or store your data. Preferably, at least one of these needs to be off-site.
|
|
|
|
Post by Paradoom on May 11, 2012 10:05:34 GMT
There is one big think everyone seems to overlook. The onboard RAID-Controller. That usually just means u have an Intel ICH 9/10/11 or whatever. Those Controllers are no true Hardware ones and will draw power from your CPU since it has to do all the calculations for the RAID-Operation. This also means you will not have the full speed wanted and possible.
The best solutions so far are already mentioned I hink: SSD for the OS and major Programms + a RAID of your normal drives.
I dont use a RAID of that kind anymore and have my important data copied to an Networkdrive for my redundancy (that runs in raid of course ^^)
|
|
|
|
Post by Yojimbo on May 11, 2012 12:41:50 GMT
I do think people over looked the on-board aspect but I have noticed a nice improvement going from RAID5 to RAID10. Mine is an AMD CPU, Chipset, & Video Card actually forget which of each but it is a decent quad core CPU.
|
|
|
|
Post by Yomi on May 12, 2012 8:17:58 GMT
I've done RAID5 with a hardware RAID unit (3ware 9650E-8port) and wasn't overjoyed. The performance was ok, but I always felt tied to that controller (and the controller isn't cheap). There was also fun of drivers with 64-bit OSes. I ended up replacing the 400GB drives with a single 2TB drive + daily backups and am much happier. Less power, less noise, fewer driver/card concerns, and just all around simpler. This relied on having a large backup server available of course.
My other Windows machines are pretty similar, with one or two drives, and backups made to the network machine. Backups are a mix of Acronis and rsnapshot (rsync daemon).
My Linux workstation sounds like Acaos' setup. SSD non-RAID for the main drive, with backups done to network machine. I have four WD Green drives (big size, inexpensive, relatively low power, low noise, but slow) in software RAID5 (mdadm).
My server runs Linux also, and has 5 2TB WD Green drives in software RAID5, for a little over 7TB of storage. It stores backups for all the other computers, and doesn't let them mount the drive directly.
As Acaos mentions, RAID solves a few problems, but still leaves you with a host of them (e.g. you delete the file, or edit it, or some wonky program decides to start overwriting stuff, or the filesystem goes corrupt). It can even add some (your controller or its driver goes nuts and destroys stuff, or it dies and now you can't read your data without buying a replacement controller). Also, since my backup server is in my same house, there are lots of not-uncommon disasters that would wipe them both out (but a lot less than a single machine). I do additional backups of really crucial data elsewhere (e.g. Quicken files, thesis, etc.).
I haven't had any issues with disk speed, but my workload is probably different. hdparm says my Vertex 3 does reads at 460 MB/s, individual WD Green drives at 90-100 MB/s, and RAID5 reads at over 250 MB/s. Since these are i7 machines the CPU load is trivial (1-10% of a single core during heavy operations). So RAID5 gives me a substantial read speedup as expected. Writes are more complicated. Using bonnie++ I see my software RAID5 using the 5400rpm green drives has higher bandwidth, lower latency, and faster operation counts on almost every measure compared to that machine's WD 7200rpm Cavier Black drive. While "Raid 5 is not the best performance" may be true compared to all other options, it's faster than a single decent-performance drive in my case. As expected, the Vertex3 SSD blew away everything else.
RAID10 seems the usual solution to give performance + redundancy. If you still have non-SSDs, I think it'll be a lot faster to go SSD drive + RAID(1/5/6) for the others, then do backups of the SSD drive. You could also do SSD drives in RAID1 or RAID10 but that gets awfully expensive. I have had no temptation to do my data drives in RAID1 or 10 due to the number of drives you end up needing. I don't see RAID10 as offering much more redundancy -- I'm far more tempted by RAID6. It also may require buying another controller since you may run out of motherboard SATA connectors. However for crucial operations I can see how it has advantages.
|
|
