… on servers for backup purpose, boxes with 64 300GB SAS drives, 3 raid controllers and 192GB of RAM. These servers will… that’s maybe just normal. We didn’t try too hard to get better performance because we already had more than… and disk usage On purpose, I allocated mirror pairs using drives from different controllers. That way, if a controller dies, the…
Post: How multiple disks can benefit for single client workload ?
April 26, 2008 By 4 Comments
… shorter. Similar affect happens to using larger hard drives – If you put 100GB on 100GB hard drive you will have it spread across all tracks, if you use 100GB non fragmented block on 1TB hard drive you… with hard drive to read/write the data you have requested. Drive has to seek to the proper track and you need drive to…
Post: How reliable RAID really is
June 30, 2006 By 13 Comments
… replacement hard drive and drive was replaced. This should be happy end of the story but in reality troubles only began. After hard drive is… was…. rebuild failed bringing all logical drive down because yet another hard drive got bad block. Replaced hard drive was “failed” because it could not…
Post: Recovering Linux software RAID, RAID5 Array
August 27, 2011 By 2 Comments
… failed hard drives in the RAID array are false positives – either simply adding drive back or re-seating the hot swap hard drive solves the… something like Drive Fitness Test (different hard drive vendors have different versions) such tools would often have a functionality to scan hard drive for bad…
Post: Is disk Everything for MySQL Performance ?
April 25, 2008 By 7 Comments
… capacity in spindles – So your hard drive can do 200 random reads per second and your SSD drive can do 10000 does it mean if you have array with 50 hard drives it would perform as… issues along you need enough concurrency to utilize multiple hard drives and with 50 drives you would need at least 50 outstanding requests…
Post: RAID and Scale Out Discussions
June 12, 2007 By 3 Comments
… indeed even have RAID available which is used for OS hard drive. Indeed using RAID for OS partition (software) is what we…. This has zero cost and offer redundancy in case of hard drive failure. Now regarding infrastructure. When being called for Consulting I… 2*2 Opterons with 32GB of RAM and 10-14 hard drives. Both solutions have comparable price/performance, though former depends on…
Post: Evaluating IO subsystem performance for MySQL Needs
March 5, 2008 By 23 Comments
I’m often asked how one can evaluate IO subsystem (Hard drive RAID or SAN) performance for MySQL needs so I’ve… which approximately matches what single drive can do. This is important lesson – even if you have many hard drives you can’t really… 2334.63 Requests/sec which is perfect scalability to 6 hard drive this array has. We have even a bit more than…
Post: Aligning IO on a hard disk RAID – the Theory
June 9, 2011 By 18 Comments
… had were rotating hard disk drives. I think the reason is very simple – when systems only had one bearing hard disk drive (HDD) as in RAID1 or one disk drive at all, you couldn’t really… when configuring RAID. Disk sectors Most if not all hard disk drives available on the market these days use 512-byte sectors…
Post: How long Innodb Shutdown may take
September 2, 2010 By 9 Comments
… at less than 200 writes/sec for single entry level hard drive to tens of thousands of writes/sec for high end… with multiple hard drives. The second important variable is your workload, especially how dirty pages would line up on the hard drive. If there… time of about 1min per GB of buffer pool per hard drive. Baron has written a nice post how to decrease innodb…
Post: Estimating Undo Space needed for LVM Snapshot
June 9, 2008 By 5 Comments
… be not to try to save too much on it. Hard drive space is often cheap these days and so it may… SATA hard drive (and so you may be able to allow full database size for undo space without thinking). If such hard drive dies… setup replication for large database with little no – connect USB hard drive place LVM snapshot on it and you can copy your…
