To speed up access to data, users are opting out of optical disk for cheaper, faster alternatives such as ATA disk...
and virtual tape.
Optical, with its WORM capability, has proven to be good for archiving. But users who have continued to deploy optical for frequently accessed files have faced slow performance, hardware failures and even outages.
Financial services firm CUNA Mutual Group, Madison, Wis., was using an IBM 3995 optical disk library to store image files containing customers' mortgage and insurance policy information.
As the number of files grew, the library became strained by too many read requests. This taxed the library's robotic arm to the point where it stalled or broke. The IT group found themselves regularly spending six hours a week fixing outages and managing the library.
CUNA moved 3.5 TB that lived on optical over to Symmetrix disk, using it as virtual tape through Diligent Technologies Corp.'s VTF Mainframe software. CUNA's choice of disk was limited because the files that were moved over resided on a mainframe.
"We've been off the optical disk for nine months and the file access time has gone from 20 seconds to under a second," said Gary Loniello, technical support analyst at CUNA.
The firm still sends backups to an optical library off site for compliance and disaster recovery.
Optical's slow performance was a problem for Bob Massengill, IT Manager at Wake Forest University Baptist Medical Center in Winston-Salem, N.C.
The center was storing reports containing patient information on an optical disk library. Like other companies let down by optical's performance, Wake Forest was experiencing data growth in both volume and importance.
"Our users needed these reports more and more and it was too much for optical," said Massengill. This led to mechanical problems. "The robotic arm would hang up or break. Sometimes we couldn't read the data and we never could figure out if it was the disk or the media."
Massengill and his staff migrated 1 TB of data onto inexpensive ATA drives on an EMC Clariion array for quicker access to files.
Another convert, Sovereign Bank spends a lot of time moving data from optical to ATA disk on their SAN because of the high cost and downtime that comes with optical.
"We acquire small banks all the time and inherit optical regularly," said Joe Ambrosino, Network Operations Manager at Sovereign. "Our favorite thing to do is convert it."
Ambrosino said he has been "shying away from optical wherever possible" because ATA is cheaper, more reliable and involves less maintenance, he said.
Even when optical is used for archiving, capacity and expense can be a problem.
Electric Insurance Company, Beverly, Mass., was using a Hewlett-Packard optical disk jukebox for long-term storage of insurance documents -- but ran into capacity issues.
"We did not expect a capacity problem with optical, but we started using our document imaging system more and more. We also began storing copies of our documents and the volume increased by an order of magnitude," said Bill Croteau, Manager of Technology Infrastructure.
Croteau and his staff converted all documents off optical to an EMC Centera to save money and improve capacity without consuming more floor space.
"Document retrieval now takes 1-2 seconds, whereas it could have required up to 30 seconds with optical," said Croteau. But he noted that for long-term storage, performance improvement was only a side benefit.
WORM works on regular disk
However optical is used, one thing is for sure: users are finding out that it's not designed for quick file access. "I think companies keep using optical because they're just used to it. But it's expensive and slow." said Jack Scott, senior partner at the Evaluator Group, Greenwood Village, Colo.
Scott added that optical is also used because of misguided compliance fears. SEC's 17a4 used to say that data had to be stored on WORM-type optical disk. But that rule was modified in May 2003, noted Scott.
"As long as you prove the data cannot be overwritten, it does not have to be WORM. Many companies still don't know this and continue using optical."