- Community Home
- >
- Servers and Operating Systems
- >
- Operating Systems
- >
- Operating System - Linux
- >
- Is Raid 5 really this bad? or...
Categories
Company
Local Language
Forums
Discussions
Forums
- Data Protection and Retention
- Entry Storage Systems
- Legacy
- Midrange and Enterprise Storage
- Storage Networking
- HPE Nimble Storage
Discussions
Discussions
Discussions
Forums
Forums
Discussions
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
- BladeSystem Infrastructure and Application Solutions
- Appliance Servers
- Alpha Servers
- BackOffice Products
- Internet Products
- HPE 9000 and HPE e3000 Servers
- Networking
- Netservers
- Secure OS Software for Linux
- Server Management (Insight Manager 7)
- Windows Server 2003
- Operating System - Tru64 Unix
- ProLiant Deployment and Provisioning
- Linux-Based Community / Regional
- Microsoft System Center Integration
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Discussion Boards
Community
Resources
Forums
Blogs
- Subscribe to RSS Feed
- Mark Topic as New
- Mark Topic as Read
- Float this Topic for Current User
- Bookmark
- Subscribe
- Printer Friendly Page
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО02-11-2010 11:03 AM
тАО02-11-2010 11:03 AM
Is Raid 5 really this bad? or...
I've setup an old Proliant DL380G2 as an NFS server that I use to backup VMware images.
But I think something is wrong because this server with its 6x144 15K disks and BBWC gets out performed (big time) by single 160 ATA disk on an 7 year old Dell Workstation.
Some info.
O.S. Debian Lenny netinstall on both machines. Running pretty much the same packages and no gui. NFS exports are on XFS and XFS under LVM control. Mount options, export settings all the same.
Workstation: A 6 or 7 year old Dell workstion with 512 mb rambus memory, a 1.8GHz P4 and 160GB 7200 ata disk. Intel PCI gigabit ethernet controller.
Server: Proliant DL380G2. 2x 1.4 Ghz PIII (Xeon? not sure) RA5300 (Ultra3) with BBWC, 6X144 15k U320 Harddisks, 2 GB Ram, NC7131 PCI-X gigabit ethernet controller. BBWC set to 75$ write. (parity data has been calculated)
I've attached some vmstat screenshots that clearly show the superiour write performance of the Dell pc. (tested with a direct link) I also added a screenshot of the servers boot log. There are some errors that might be related.(I tried noapic) Or perhaps Raid 5 is just this slow and I'm wasting my and your time.
WB
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО02-11-2010 12:57 PM
тАО02-11-2010 12:57 PM
Re: Is Raid 5 really this bad? or...
Raid 5 is going to be slow on heavy write applications. The data has to be written to more places.
Raid 5 parity 9 requires everything be in 45 different places. This takes time.
SEP
Owner of ISN Corporation
http://isnamerica.com
http://hpuxconsulting.com
Sponsor: http://hpux.ws
Twitter: http://twitter.com/hpuxlinux
Founder http://newdatacloud.com
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО02-11-2010 04:27 PM
тАО02-11-2010 04:27 PM
Re: Is Raid 5 really this bad? or...
These are 6x 15.000 rpm disks!
Writes are on average not even 1/4 of the Dell pc's speed.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО02-12-2010 08:39 AM
тАО02-12-2010 08:39 AM
Re: Is Raid 5 really this bad? or...
(Ok, maybe it must have been finetuned by a more competent person.)
Unix operates with beer.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО02-12-2010 08:44 AM
тАО02-12-2010 08:44 AM
Re: Is Raid 5 really this bad? or...
I need to do reconfigure on a production server tonigh. Maybee I have time to convert the server to Raid 10.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО02-12-2010 02:38 PM
тАО02-12-2010 02:38 PM
Re: Is Raid 5 really this bad? or...
Performance is a bit better but still less then half the speed of the dell workstation.
So something is clearly wrong.
I've run an Iperf test betwwen the server and the workstation and it only scores about 300mbit. So perhaps the NC7131 NIC is the bottleneck. Perhaps the NIC needs proprietary firmware installed?
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО02-15-2010 01:56 AM
тАО02-15-2010 01:56 AM
Re: Is Raid 5 really this bad? or...
Good point. I didn't realize it, because your config wasn't really clear until now. It is a Gbit card with 1024Mbit/sec _theoretical_max_speed_ which is ~128Mbyte _theoretical_ speed, so without the tcp headers, collision and the other overhead it is around 100Mbyte/sec, which is also theoretical max. If you have any other elements on the subnet the speed is much less. So don't expect too much from it, or go get a second NIC and do bonding.
(btw. how it is connected to the backup system? Switch/Hub? Speed? What's on the other side?)
Anyway, I wouldn't choose RAID5 unless I have a high quality RAID controller which is around 500USD. IMHO software RAID5 don't deliver the expected results, a cheap HW RAID5 is also not a solution worth to config. The parity should be computed live, on the fly. On the high-end RAID controllers there is enough cache read from/to, which is a serious performance growth. So RAID 1+0 seems a good decision. ;)
Unix operates with beer.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО02-15-2010 02:04 AM
тАО02-15-2010 02:04 AM
Re: Is Raid 5 really this bad? or...
But I'm not sure if this is going to work since this will mean mixing pci (NIC) with pci-x (RA5300)
But performance is so bad it would probably fit a 100mbit connection.
If things won't improve I'll try installing CentOS 4.8. HP has some drives for RHEL 4 so that will probably also work with CentOS.
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО02-15-2010 04:10 AM
тАО02-15-2010 04:10 AM
Re: Is Raid 5 really this bad? or...
But write performance to the server still sucks.
Question: I'm mixing pci with pci-x on the server. Will there be a performance pennalty for the pci-x device?
- Mark as New
- Bookmark
- Subscribe
- Mute
- Subscribe to RSS Feed
- Permalink
- Report Inappropriate Content
тАО02-15-2010 07:38 AM
тАО02-15-2010 07:38 AM
Re: Is Raid 5 really this bad? or...
Also the pci-x NIC is performing much better.