----- Original Message ----- > From: "Joseph Spenner" <joseph85...@yahoo.com> > To: "CentOS mailing list" <centos@centos.org> > Sent: Thursday, April 11, 2013 1:36:29 PM > Subject: Re: [CentOS] RAID 6 - opinions > > > > > ________________________________ > From: John R Pierce <pie...@hogranch.com> > To: centos@centos.org > Sent: Thursday, April 11, 2013 1:24 PM > Subject: Re: [CentOS] RAID 6 - opinions > > > On 4/11/2013 12:30 PM, m.r...@5-cent.us wrote: > >> Ok, listening to all of this, I've also been in touch with a tech > >> from the > >> vendor*, who had a couple of suggestions: first, two RAID sets > >> with two > >> global hot spares. > > > I would test how long a drive rebuild takes on a 20 disk RAID6. I > suspect, very long, like over 24 hours, assuming a fast controller > and > sufficient channel bandwidth. >
Just for reference, I have a 24 x 2TB SATAIII using CentOS 6.4 Linux MD RAID6 with two of those 24 disks as hotspares. The drives are in a Supermicro external SAS/SATA box connected to another Supermicro 1U computer with an i3-2125 CPU @ 3.30GHz and 16GB ram. The connection is via a 6Gbit mini SAS cable to an LSI 9200 HBA. Before I deployed it into production I tested how long it would take to rebuild the raid from one of the hot spares and it took a little over 9 hours. I have two 15TB LVM's on it formatted EXT4 with the rest used for LVM snapshot space if needed. Using dd to write a large file to one of the partitions I see about 480MB/s. If I rsync from one partition to another I get just under 200MB/s. dd if=/dev/zero of=/backup/5GB.img count=5000 bs=1M 5000+0 records in 5000+0 records out 5242880000 bytes (5.2 GB) copied, 10.8293 s, 484 MB/s David. _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
